Image Processing Sensor, Image Processing Method, Image Processing Program, And Computer-Readable Recording Medium And Device Having Image Processing Program Recorded Therein

ABSTRACT

An image processing sensor includes an image registering unit configured to register a non-defective product image, a defective product image, and a background image, a differential-image generating unit configured to generate a first differential image from the non-defective product image and the background image and generate a second differential image from the defective product image and the background image; a matching-degree calculating unit configured to calculate a matching degree indicating a degree of feature matching of the second differential image with respect to a model image corresponding to the first differential image, and a threshold calculating unit configured to calculate, on the basis of the matching degree, a threshold used in an operation mode.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims foreign priority based on Japanese PatentApplication No. 2016-117055, filed Jun. 13, 2016, the contents of whichis incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to an image processing sensor, an imageprocessing method, an image processing program, and a computer-readablerecording medium and a device having the image processing programrecorded therein.

2. Description of Related Art

An image processing sensor is set in various forms. For example, as amember for inspecting the exterior of an inspection target objectvisually, the image processing sensor is set near a conveyance line onwhich the inspection target object is conveyed or is incorporated in atest apparatus.

For example, the image processing sensor images, as the inspectiontarget object, work flowing on a production line and detects presence orabsence of a defect of the work on the basis of obtained images and apreset threshold to thereby perform pass/fail determination of the work.A user needs to acquire an image obtained by imaging non-defective workin advance and register the image as a model image. This work is calledteaching (e.g., JP-A-11-312249).

However, in such an image processing sensor, since the teaching isperformed by only the registration of the model image, for example,registration of a non-model image not including the non-defective workcannot be performed. Therefore, the threshold used for the pass/faildetermination of the work has to be calculated from only the modelimage. As a result, it is not easy to determine a threshold that canstably separate a non-defective product and a defective product. Even iftwo images, that is, a model image and a non-model image can beregistered, if operation and a procedure for registering the model imageand the non-model image are complicated, it is difficult for a userunfamiliar with setting work to use the image processing sensor.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an image processingsensor, an image processing method, an image processing program, and acomputer-readable recording medium and a device having the imageprocessing program recorded therein that make it possible to easilyperform setting of a threshold necessary for stably separating anon-defective product and a defective product.

An image processing sensor according to a first aspect of the presentinvention is an image processing sensor for performing predeterminedimage processing on an image of an inspection target object to detectthat the inspection target object is a non-defective product or adefective product. The image processing sensor includes: an imaging unitconfigured to image the inspection target object; a pass/faildetermining unit configured to perform, on the basis of an input imageof the inspection target object acquired by the imaging unit, pass/faildetermination for distinguishing pass/fail of the inspection targetobject; an image registering unit configured to, in a setting mode forcalculating a threshold serving as a reference of the pass/faildetermination used in an operation mode for distinguishing the pass/failof the inspection target object by the pass/fail determining unit,acquire, with the imaging unit, an image including the inspection targetobject that should be distinguished as the non-defective product by thepass/fail determining unit and register the image as a non-defectiveproduct image, acquire, with the imaging unit, an image including theinspection target object that should be distinguished as the defectiveproduct by the pass/fail determining unit and register the image as adefective product image, and acquire, with the imaging unit, an image ofa background from which a feature portion of the non-defective productin the inspection target object is removed and register the image as abackground image; a differential-image generating unit configured togenerate a first differential image from the non-defective product imageand the background image registered by the image registering unit andgenerate a second differential image from the defective product imageand the background image registered by the image registering unit; amatching-degree calculating unit configured to calculate a matchingdegree indicating a degree of feature matching of the seconddifferential image with respect to a model image corresponding to thefirst differential image generated by the differential-image generatingunit; and a threshold calculating unit configured to calculate, on thebasis of the matching degree calculated by the matching-degreecalculating unit, a threshold used in the operation mode. With theconfiguration explained above, it is possible to prevent the operationmode from being easily affected background elements and preventdeterioration in defect detection accuracy in the operation mode. It ispossible to easily perform setting work necessary for obtaining such aresult.

According to a second aspect of the present invention, in addition tothe configuration explained above, the image processing sensor mayfurther include: a display unit configured to display an image of theinspection target object acquired by the imaging unit; an operation unitconfigured to receive an operation instruction for registering the imagedisplayed by the display unit; and a display control unit configured tocause the display unit to display the non-defective product image asalive image on a first registration screen for registering thenon-defective product image on the basis of the operation instructionreceived from the operation unit, cause the display unit to display thedefective product image as the live image on a second registrationscreen for registering the defective product image on the basis of theoperation instruction received from the operation unit, and cause thedisplay unit to display the background image as the live image on athird registration screen for registering the background image on thebasis of the operation instruction received from the operation unit. Theimage registering unit may register, on the basis of a first instructionreceived from the operation unit, the non-defective product imagedisplayed by the display unit on the first registration screen,register, on the basis of a second instruction received from theoperation unit, the defective product image displayed by the displayunit on the second registration screen, and register, on the basis of athird instruction received from the operation unit, the background imagedisplayed by the display unit on the third registration screen.

Further, according to a third aspect of the present invention, in theimage processing sensor, in one of the configurations explained above,the display control unit may cause the display unit to display, on thesecond registration screen, as a still image, the non-defective productimage registered on the first registration screen by the imageregistering unit.

Furthermore, according to a fourth aspect of the present invention, inaddition to any one of the configurations, the image processing sensormay further include an operation/setting-mode switching unit configuredto switch the operation mode for distinguishing the pass/fail of theinspection target object with the pass/fail determining unit and thesetting mode for calculating a threshold used in the operation mode.

Furthermore, according to a fifth aspect of the present invention, inaddition to anyone of the configurations explained above, the imageprocessing sensor may further include a teaching-mode switching unitconfigured to selectively switch, in the setting mode switched by theoperation/setting-mode switching unit, a second teaching mode forswitching and displaying, on the display unit, any one of the firstregistration screen, the second registration screen, and the thirdregistration screen and a first teaching mode for switching anddisplaying, on the display unit, one of the first registration screenand the third registration screen. When the second teaching mode isselected by the teaching-mode switching unit, the display control unitmay cause the display unit to display the non-defective product image asa live image on the first registration screen, cause the display unit todisplay the defective product image as the live image on the secondregistration screen, and cause the display unit to display thebackground image as the live image on the third registration screen. Onthe other hand, when the first teaching mode is selected by theteaching-mode switching unit, the display control unit may cause thedisplay unit to display the non-defective product image as the liveimage on the first registration screen and cause the display unit todisplay the background image as the live image on the third registrationscreen.

Furthermore, according to a sixth aspect of the present invention, inaddition to anyone of the configurations explained above, the imageprocessing sensor may further include a teaching-mode switching unitconfigured to selectively switch, in the setting mode switched by theoperation/setting-mode switching unit, a second teaching mode forswitching and displaying, on the display unit, any one of the firstregistration screen, the second registration screen, and the thirdregistration screen and a first teaching mode for switching anddisplaying, on the display unit, one of the first registration screenand the third registration screen. When the first teaching mode isselected by the teaching-mode switching unit, the differential-imagegenerating unit may generate the first differential image from thenon-defective product image and the background image and thematching-degree calculating unit may calculate a matching degreeindicating a degree of feature matching of the background image withrespect to the model image corresponding to the first differential imagegenerated by the differential-image generating unit.

Furthermore, according to a seventh aspect of the present invention, inaddition to anyone of the configurations explained above, the imageprocessing sensor may further include a feature-region extracting unitconfigured to extract feature image regions from the first differentialimage and the second differential image. The matching-degree calculatingunit may calculate a matching degree indicating a degree of featurematching of the second differential image with respect to the featureimage region extracted from the first differential image by thefeature-region extracting unit.

Furthermore, according to an eighth aspect of the present invention, inthe image processing sensor, in addition to any one of theconfigurations explained above, the model image may include adifferential image or an edge image.

Furthermore, according to a ninth aspect of the present invention, inthe image processing sensor, in addition to any one of theconfigurations explained above, the teaching-mode switching unit may befurther capable of selecting a third teaching mode for displaying thethird registration screen on the display unit in the setting modeswitched by the operation/setting-mode switching unit. When the thirdteaching mode is selected by the teaching-mode switching unit, thematching-degree calculating unit may calculate a feature value of thebackground image registered by the image registering unit and thethreshold calculating unit may calculate, on the basis of the featurevalue of the background image calculated by the matching-degreecalculating unit, a threshold used in the operation mode.

Furthermore, according to a tenth aspect of the present invention, inthe image processing sensor, in addition to any one of theconfigurations explained above, the display control unit may at leastcause the display unit to display, on the first registration screen,first induction information for inducing registration of thenon-defective product image and cause the display unit to display, onthe third registration screen, third induction information for inducingregistration of the background image.

Furthermore, according to an eleventh aspect of the present invention,in the image processing sensor, in addition to any one of theconfigurations explained above, the display control unit may at leastcause the display unit to display, on the second registration screen,second induction information for inducing registration of the defectiveproduct image.

Furthermore, according to a twelfth aspect of the present invention, inthe image processing sensor, in addition to any one of theconfigurations explained above, the display control unit may provide, inthe display unit, an image display region where an image is displayedand cause the display unit to display, in the image display region,guide lines serving as indicators for positioning in placing theinspection target object in an imaging position.

Furthermore, according to a thirteenth aspect of the present invention,in the image processing sensor, in addition to any one of theconfigurations explained above, the display control unit may be capableof displaying, on the display unit, registration order informationindicating registration order for performing image registration of thenon-defective product image, the defective product image, or thebackground image.

An image processing method according to a fourteenth aspect of thepresent invention is an image processing method for performingpredetermined image processing on an image of an inspection targetobject to detect that the inspection target object is a non-defectiveproduct or a defective product. The image processing method includes: astep of, in a setting mode for calculating a threshold serving as areference of pass/fail determination used in an operation mode fordistinguishing pass/fail with a pass/fail determining unit configured todetermine pass/fail of the inspection target object, acquiring, with animaging unit configured to image the inspection target object, an imageincluding the inspection target object that should be distinguished asthe non-defective product by the pass/fail determining unit andregistering the image as a non-defective product image with an imageregistering unit, acquiring, with the imaging unit, an image includingthe inspection target object that should be distinguished as thedefective product by the pass/fail determining unit and registering theimage as a defective product image with the image registering unit, andacquiring, with the imaging unit, an image of a background from which afeature portion of the non-defective product in the inspection targetobject is removed and registering the image as a background image withthe image registering unit; a step of generating a first differentialimage from the non-defective product image and the background imageregistered by the image registering unit and generating a seconddifferential image from the defective product image and the backgroundimage registered by the image registering unit; a step of calculating amatching degree indicating a degree of feature matching of the seconddifferential image with respect to a model image corresponding to thefirst differential image; and a step of calculating, on the basis of thematching degree, a threshold used in the operation mode. Consequently,it is possible to prevent the operation mode from being easily affectedbackground elements and prevent deterioration in defect detectionaccuracy. It is possible to easily perform setting work necessary forobtaining such a result.

Furthermore, an image processing program according to a fifteenth aspectof the present invention is an image processing program for performingpredetermined image processing on an image of an inspection targetobject to detect that the inspection target object is a non-defectiveproduct or a defective product. The image processing program causes acomputer to realize: in a setting mode for calculating a thresholdserving as a reference of pass/fail determination used in an operationmode for distinguishing pass/fail with a pass/fail determining unitconfigured to determine pass/fail of the inspection target object, afunction of acquiring, with an imaging unit, an image including theinspection target object that should be distinguished as thenon-defective product by the pass/fail determining unit and registeringthe image as a non-defective product image; a function of acquiring,with the imaging unit, an image including the inspection target objectthat should be distinguished as the defective product by the pass/faildetermining unit and registering the image as a defective product image;and a function of acquiring, with the imaging unit, an image of abackground from which a feature portion of the non-defective product inthe inspection target object is removed and registering the image as abackground image; a function of generating a first differential imagefrom the registered non-defective product image and the registeredbackground image and generating a second differential image from thedefective product image and the background image; a function ofcalculating a matching degree indicating a degree of feature matching ofthe second differential image with respect to a model imagecorresponding to the first differential image; and a function ofcalculating, on the basis of the matching degree, a threshold used inthe operation mode. With the configuration explained above, it ispossible to prevent the operation mode from being easily affectedbackground elements and prevent deterioration in defect detectionaccuracy. It is possible to easily perform setting work necessary forobtaining such a result.

Furthermore, a computer-readable recording medium having a computerprogram stored therein or a device having the computer program recordedtherein according to a sixteenth aspect of the present invention storesthe computer program. Examples of the recording medium include magneticdisks, optical disks, and magneto-optical disks such as a CD-ROM, aCD-R, a CD-RW, a flexible disk, a magnetic tape, an MO, a DVD-ROM, aDVD-RAM, a DVD-R, a DVD+R, a DVD-RW, a DVD+RW, a Blu-ray (registeredtrademark) disk, and a HD DVD, a semiconductor memory, and other mediacapable of storing computer programs. Examples of the computer programinclude, besides computer programs stored in the recording media anddistributed, a computer program of a form distributed by downloadthrough a network line such as the Internet. Examples of the devicehaving the computer program recorded therein include a general-purposeor dedicated device in which the computer program is implemented in astate in which the computer program is executable in a form of software,firmware, or the like. Furthermore, kinds of processing and functionsincluded in the computer program may be executed by program softwareexecutable by a computer. Processing of units may be realized byhardware such as a predetermined gate array (FPGA or ASIC) or in a formin which the program software and a partial hardware module forrealizing a part of elements of the hardware are mixed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram showing an image processing sensoraccording to a first embodiment of the present invention.

FIG. 1B is a schematic diagram showing an image processing sensoraccording to a second embodiment of the present invention.

FIG. 2A is a perspective view of the image processing sensor shown inFIGS. 1B viewed from a rear obliquely downward direction and FIG. 2B isa vertical sectional view of the image processing sensor.

FIG. 3A is a schematic diagram showing a display surface of the imageprocessing sensor according to the second embodiment.

FIG. 3B is a schematic diagram showing a display surface of an imageprocessing sensor according to a modification.

FIG. 3C is a schematic diagram showing a display surface of an imageprocessing sensor according to another modification.

FIG. 3D is a schematic diagram showing an image processing sensor inwhich a display unit is reversely displayed.

FIG. 4 is a block diagram of an image processing sensor.

FIG. 5 is a block diagram showing functions of the image processingsensor.

FIG. 6 is a flowchart for explaining a procedure of two-pointregistration for registering a non-defective product image and adefective product image.

FIG. 7 is an image diagram showing an operation screen of the displayunit.

FIG. 8 is an image diagram showing an example of a first registrationscreen during the two-point registration.

FIG. 9 is an image diagram showing a state in which a non-defectiveproduct image is displayed in FIG. 8.

FIG. 10 is an image diagram showing an image enlarging and reducingfunction.

FIG. 11 is an image diagram showing an example of a second registrationscreen during the two-point registration. An image diagram showing anexample in which a background image is displayed excluding work fromFIG. 9.

FIG. 12 is a flowchart for explaining a procedure of two-pointregistration for registering a non-defective product image and abackground image.

FIG. 13 is an image diagram showing a second registration screen forregistering an image “without detected work” during the two-pointregistration.

FIG. 14A is a schematic diagram showing a state in which a simpledifferential image from which only non-defective work is extracted isgenerated excluding a background image from a non-defective productimage and FIG. 14B is a schematic diagram showing a state in whichsimple differential image from which only defective work is extracted isgenerated excluding the background image from a defective product image.

FIG. 15A is a flowchart for explaining a part of a procedure ofthree-point registration.

FIG. 15B is a flowchart for explaining a procedure of the three-pointregistration following FIG. 15A.

FIG. 16 is an image diagram showing an example of a first registrationscreen during the three-point registration.

FIG. 17 is an image diagram showing an example of a second registrationscreen during the three-point registration.

FIG. 18 is an image diagram showing an example of a third registrationscreen during the three-point registration.

FIG. 19 is a flowchart for explaining a procedure of one-pointregistration for registering a non-defective product image or abackground image.

FIG. 20 is an image diagram showing a background image.

FIG. 21 is an image diagram showing a state in which an evaluationregion is set with respect to the background image shown in FIG. 20.

FIG. 22 is a table showing an example of matching degree thresholdsetting.

FIG. 23 is an image diagram showing another example of the firstregistration screen during the two-point registration.

FIG. 24 is an image diagram showing another example of the secondregistration screen during the two-point registration.

FIG. 25 is an image diagram showing still another example of the firstregistration screen during the two-point registration.

FIG. 26 is an image diagram showing still another example of the secondregistration screen during the two-point registration.

FIG. 27 is an image diagram showing an example in which the firstregistration screen is switched and displayed.

FIG. 28 is an image diagram showing an example in which the secondregistration screen is switched and displayed.

FIG. 29 is an image diagram showing an example in which candidate imagesabout to be registered and registered non-defective product images areswitched and displayed on the second registration screen.

FIG. 30 is an image diagram showing an example in which the candidateimages about to be registered and parallel display are switched anddisplayed on the second registration screen.

FIG. 31 is an image diagram showing an example in which the secondregistration screen during the three-point registration is a paralleldisplay screen.

FIG. 32 is a flowchart for explaining a procedure of still image/liveimage simultaneous display.

FIG. 33 is an image diagram showing an example in which the thirdregistration screen during the three-point registration is a paralleldisplay screen.

FIG. 34 is an image diagram showing an example in which an image displayregion and an explanation display region are caused to partiallyoverlap.

FIG. 35 is an image diagram showing an example in which the imagedisplay region and the explanation display region are caused tocompletely overlap.

FIG. 36 is a schematic diagram showing a state in which an operationmode and a setting mode are switched.

FIG. 37A is a flowchart for explaining an example of screen transitionof the operation mode.

FIG. 37B is a flowchart for explaining the example of the screentransition of the operation mode.

FIG. 38A is a flowchart for explaining the operation of the setting modeincluding a step for adjusting image display magnification.

FIG. 38B is a flowchart for explaining the operation of the operationmode including a step of adjusting a matching degree threshold.

FIG. 39 is a block diagram showing internal processing of a conventionalimage processing sensor.

FIG. 40 is a block diagram showing internal processing of an imageprocessing sensor according to an embodiment.

FIG. 41 is a schematic diagram showing a state in which an image isreduced in resolution.

FIG. 42 is a schematic diagram showing a state in which image data isaveraged and compressed.

FIG. 43 is a schematic diagram showing a state in which image data iscurtailed and compressed.

FIG. 44A is a flowchart for explaining a procedure of setting andoperation of two-point registration of a non-defective product image anda background image including resolution reduction processing, FIG. 44Bis an image diagram showing an example of the non-defective productimage, FIG. 44C is an image diagram showing an example of the backgroundimage, FIG. 44D is an image diagram showing an example of a compressednon-defective product image, FIG. 44E is an image diagram showing anexample of a compressed background image, and FIG. 44F is an imagediagram showing an example of a compressed non-defectiveproduct-background differential image.

FIG. 45A is a flowchart for explaining a procedure of setting andoperation of two-point registration of a non-defective product image anda background image including the resolution reduction processing, FIG.45B is an image diagram showing an example of the non-defective productimage, FIG. 45C is an image diagram showing an example of the backgroundimage, FIG. 45D is an image diagram showing an example of anon-defective product-background differential image, and FIG. 45E is animage diagram showing an example of a compressed non-defectiveproduct-background differential image.

FIG. 46A is a flowchart for explaining a procedure of setting andoperation of three-point registration of a non-defective product image,a defective product image, and a background image including theresolution reduction processing, FIG. 46B is an image diagram showing anexample of the non-defective product image, FIG. 46C is an image diagramshowing an example of the defective product image, FIG. 46D is an imagediagram showing an example of the background image, FIG. 46E is an imagediagram showing an example of a compressed non-defective product image,FIG. 46F is an image diagram showing an example of a compresseddefective product image, FIG. 46G is an image diagram showing an exampleof a compressed background image, FIG. 46H is an image diagram showingan example of a compressed non-defective product-background differentialimage, and FIG. 46I is an image diagram showing an example of acompressed defective product-background differential image.

FIG. 47A is a flowchart for explaining a procedure of setting andoperation of three-point registration of a non-defective product image,a defective product image, and a background image including theresolution reduction processing, FIG. 47B is an image diagram showing anexample of the non-defective product image, FIG. 47C is an image diagramshowing an example of the defective product image, FIG. 47D is an imagediagram showing an example of the background image, FIG. 47E is an imagediagram showing an example of a non-defective product-backgrounddifferential image, FIG. 47F is an image diagram showing an example of adefective product-background differential image, FIG. 47G is an imagediagram showing an example of a compressed non-defectiveproduct-background differential image, and FIG. 47H is an image diagramshowing an example of a compressed defective product-backgrounddifferential image.

FIG. 48A is a flowchart for explaining a procedure of one-pointregistration for registering a background image including the resolutionreduction processing, FIG. 48B is an image diagram showing thebackground image, and FIG. 48C is an image diagram showing a compressedbackground image.

FIG. 49A is a schematic diagram showing a procedure for determining anoptimum brightness condition of an image when a response time can beset.

FIG. 49B is a schematic diagram showing a procedure for determining anoptimum brightness condition of an image when the response time is adefault value.

FIG. 50 is a flowchart for explaining a procedure for findingappropriate registration setting conditions from a candidate group ofregistration setting conditions and performing image registration.

FIG. 51A is a flowchart for explaining a series of image processingbefore replacement of an image processing algorithm, FIG. 51B is aflowchart for explaining a series of image processing after replacementof a part of the image processing algorithm from FIG. 51A, FIG. 51C isan image diagram showing a non-defective product image, FIG. 51D is animage diagram showing a defective product image, FIG. 51E is an imagediagram showing a background image, FIG. 51F is an image diagram showingan evaluation image, FIG. 51G is an image diagram showing an image ofwork, FIG. 51H is an image diagram showing an image of the work cut outfrom the evaluation image shown in FIG. 51F, FIG. 51I is an imagediagram showing an image of a region of the work cut out by differentialprocessing of the evaluation image shown in FIG. 51F and the backgroundimage shown in FIG. 51E, and FIG. 51J is an image diagram showing a workregion cut out from the evaluation image shown in FIG. 51H.

FIG. 52A is a flowchart for explaining a series of image processingbefore replacement of constituent elements of the image processingalgorithm and FIG. 52B is a flowchart for explaining a series of imageprocessing after the replacement of the constituent elements of theimage processing algorithm from FIG. 52A.

FIG. 53A is a schematic diagram showing Sobel X of a Sobel filter, FIG.53B is a schematic diagram showing Sobel Y, and FIG. 53C is a schematicdiagram showing X and Y components of an edge applied with Sobel X andSobel Y.

FIG. 54A is a schematic diagram showing Roberts X, FIG. 54B is aschematic diagram showing Roberts Y, and FIG. 54C is a schematic diagramshowing X and Y components of an edge applied with Roberts X and RobertsY.

FIG. 55 is an image diagram showing a state in which non-defective workand defective work flow on a manufacturing line.

FIG. 56A is a schematic diagram of showing a flow of work for explainingan output state at the time when a master image is a non-defectiveproduct image, FIG. 56B is a graph showing a time series change of afirst matching degree, FIG. 56C is a schematic diagram showing a timeseries change of an output, and FIG. 56D is a schematic diagram showinga time series change of an output at the time when setting for reversingan output logic with respect to the time series change of the outputshown in FIG. 56C or changing the output to ON when the matching degreeis smaller than a threshold.

FIG. 57A is a schematic diagram showing a flow of work for explaining anoutput state at the time when the master image is a defective productimage, FIG. 57B is a graph showing a time series change of a secondmatching degree, and FIG. 57C is a schematic diagram showing a timeseries change of an output.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention are explained below with referenceto the drawings. However, the embodiments explained below areillustrations for embodying the technical idea of the present invention.The present invention is not limited to the embodiments explained below.This specification does not limit members explained in claims to membersexplained in the embodiments. Dimensions, materials, shapes, relativedispositions, and the like of constituent components described in theembodiments are not meant to limit the scope of the present inventiononly thereto unless specifically described otherwise and are only mereexplanation examples. Note that sizes, positional relations, and thelike of the members shown in the drawings are sometimes exaggerated toclarify explanation. Further, in the following explanation, the samenames and the same reference numerals and signs indicate the same orhomogenous members. Detailed explanation of the members is omitted asappropriate. Further, as elements configuring the present invention, aplurality of elements maybe configured by the same member and one membermay be used as the plurality of elements. Conversely, a function of onemember can be shared and realized by a plurality of members.

First Embodiment

An image processing sensor 100 according to a first embodiment of thepresent invention is shown in FIG. 1A. An image processing sensor 200according to a second embodiment is shown in FIG. 1B. The imageprocessing sensors capture an image of an inspection target object(hereinafter referred to as “work (WK)” as well and performs imageprocessing on the image to determine or detect that the inspectiontarget object is a non-defective product or a defective product. Theimage processing sensors can perform, by outputting determination resultto the outside, necessary post processing such as confirmation of thenon-defective product or removal of the defective product on the basisof an output of an inspection result.

The image processing sensors can be switched to an operation mode forperforming the determination of the non-defective product and thedefective product and a setting mode for performing setting. In thesetting mode, a user can register a model image such as a non-defectiveproduct image obtained by imaging the non-defective product. A matchingdegree threshold serving as a reference in the determination of thenon-defective product and the defective produce is set on the basis ofthe registered model image (details are explained below). Such settingwork performed prior to operation is called teaching or the like.

FIG. 1A shows the image processing sensor 100 of a separated type inwhich a head unit 2 and a controller unit 3 are separated. FIG. 1B showsthe image processing sensor 200 of an integrated type in which a headunit and a controller unit are integrated. A perspective view of theimage processing sensor 200 shown in FIG. 1B viewed from a rearobliquely downward direction is shown in FIG. 2A. A vertical sectionalview of the image processing sensor 200 is shown in FIG. 2B.

The head unit 2 shown in FIG. 1A includes an imaging unit 21 such as acamera and an illuminating unit 26. On the other hand, the controllerunit 3 is a member for performing image processing on an image capturedby the head unit 2 and is called amplifier unit as well. The head unit 2and the controller unit 3 can be respectively housed in differentcasings (housings) as shown in FIG. 1A or can be housed in a commoncasing 40 as shown in FIG. 1B. The illuminating unit of the head unitcan be provided separately from the camera. In the followingexplanation, mainly as the exterior of the image processing sensor, thecasing 40 in which the head unit and the controller unit shown in FIG.1B are integrated is explained. However, the controller unit 3 shown inFIG. 1A is basically the same.

Note that even the controller unit alone functions as an imageprocessing sensor. In this case, an image input unit for taking in animage captured by an external device such as the head unit functions asan image acquiring unit.

(Casing 40)

The casing 40 of the image processing sensor is configured in ahexahedron shape configured from upper and lower surfaces, left andright surfaces, and front and rear surfaces. Among the surfaces, theupper surface is set as a first principal plane and the lower surfaceopposed to the upper surface is set as a second principal plane. Asshown in FIGS. 2A and 2B, a display unit 43 and an operation unit 51 areprovided on the second principal plane on the lower surface side. On theother hand, the display unit 43 and the operation unit 51 are providedon the first principal plane on the upper surface side. In this way, thesecond principal plane on the bottom surface side is set as an imagingsurface 40 b and the first principal plane on the upper surface side isset as a display surface 40 a. Consequently, it is possible to displayan image captured by the imaging surface 40 b on the display surface 40a and match a disposition posture and a layout of the image processingsensor 200.

The imaging unit 21 is a member for capturing an image of work and isconfigured by a camera and the like. As the camera, an imaging elementsuch as a CMOS or a CCD can be used. In this case, an image captured bythe imaging unit 21 is an optical image. Note that, when an imaging unitcapable of measuring height information is used, a height image obtainedby converting height information into luminance can also be used suchthat an image having the height information can be treated in the samemanner as a two-dimensional optical image.

The illuminating unit 26 is a member for irradiating illumination lightwhen an image of work is captured by the imaging unit 21. As a lightsource of the illumination light, an LED, an organic EL, an incandescentlamp, a halogen lamp, and the like can be used. As the illuminationlight, various colors can be used. For example, when conveying speed ofa line is high, an exposure time that can be consumed to capture oneoptical image decreases. Therefore, it is desirable to adopt a lightsource having a large light amount such that sufficient brightness canbe secured in a short time. Form such a viewpoint, a red color or thelike with which a light source is inexpensive and a light amount can beeasily obtained can be suitably used. White light and infrared light maybe used. Alternatively, depending on a color and a material ofdistinction target work, an illumination color that is easily determinedis sometimes present. In this case, the illumination color can also beincluded in parameters of brightness conditions.

As shown in the sectional view of FIG. 2B, the imaging unit 21 isdisposed in parallel to the imaging surface 40 b and configured suchthat the optical axis of the imaging element is substantially orthogonalto the imaging surface 40 b. Consequently, it is possible to capture anorthogonal image of an inspection target object present in an imagingposition below the image processing sensor. On the other hand, a lightprojection surface of the illuminating unit 26 is slightly inclined withrespect to the imaging surface 40 b. Since the optical axis of theillumination light is set oblique to the optical axis of the imagingelement, it is possible to capture an image with a natural shadow. Notethat, in the example shown in FIG. 2A, one light source of theillumination light is provided. However, a plurality of light sourcescan also be provided. For example, illumination light sources areprovided at four corners of the imaging surface to surround the imagingunit. Consequently, it is possible to obtain an image with a lessshadow.

(Display Surface 40 a)

An example of the display surface 40 a is shown in the schematic diagramof FIG. 3A. The display surface 40 a is formed in a rectangular shapelong in one direction. As shown in the figure, the operation unit 51 isprovided on the display surface 40 a of the image processing sensor 200in addition to the display unit 43. The operation unit 51 includes a SETkey 42 equivalent to a determination key for instructing determinationsuch as an image registration button, up/down keys 44 equivalent to anincrease/decrease adjusting unit 51 h (FIG. 5 referred to below), a BACKkey 45 equivalent to a cancellation instructing unit, and a MODE key 46equivalent to an operation/setting-mode switching unit 51 d (FIG. 5referred to below) (details are explained below). Further, a displaylamp is provided on the display surface 40 a. The display lamp includesa determination-result display lamp 41 and an output-state display lamp47.

(Display Unit 43)

The display unit 43 is a member for displaying an image of work capturedby the imaging unit 21. As the display unit 43, a display of organic EL,liquid crystal, or the like can be used.

(Increase/Decrease Adjusting Unit 51 h)

The increase/decrease adjusting unit 51 h is configured by a pair ofmembers, that is, a switch on an up-side and a switch on a down-side.The increase/decrease adjusting unit 51 h is used to, for example,change display magnification of an image displayed on the display unit43. The image displayed by the display unit 43 is, for example, a firstimage such as a non-defective product image, a second image such as adefective product image, and a third image such as a background image.In particular, the display magnification is adjusted by theincrease/decrease adjusting unit 51 h in order to enlarge and displaythe non-defective product image and non-defective product candidateimages. The matching degree threshold can also be adjusted by the sameincrease/decrease adjusting unit 51 h (details of these kinds ofadjustment work are explained below). In this example, it is possible togive an instruction such that, when the switch on the up-side isoperated, the magnification of the first image and the matching degreethreshold increase and, when the switch on the down-side is operated,the magnification of the first image and the matching degree thresholddecrease. In this way, the increase/decrease adjusting unit 51 h enablesdifferent kinds of operation, that is, an adjusting function for imagedisplay magnification and an adjusting function for the matching degreethreshold. The common increase/decrease adjusting unit 51 h is used foradjustment of different values to reduce the number of operation buttonsthat should be provided in the display unit, avoid an increase in thesize of the display unit, and avoid complication of operation due to anincrease in the operation buttons. Consequently, simplification of aconfiguration, improvement of operability, a reduction in cost, and thelike are achieved. (Switching of the functions of the increase/decreaseadjusting unit)

The switching of the functions of the increase/decrease adjusting unitmay be performed after the functions of the increase/decrease adjustingunit are selected. However, in this case, before the increase/decreaseadjusting unit is operated, operation for selecting and switching thefunctions of the increase/decrease adjusting unit is essential. The useris forced to perform complicated operation. Therefore, the functionswitching is configured to be automatically executed such that,according to operation modes currently being selected, the functions ofthe increase/decrease adjusting unit change to functions suitable forthe operation modes. Consequently, it is possible to eliminate the needfor the operation of the function switching of the increase/decreaseadjusting unit. For example, in a state in which the setting mode isselected by the operation/setting-mode switching unit 51 d, a functionof changing the image display magnification is allocated to theincrease/decrease adjusting unit 51 h. On the other hand, in a state inwhich the operation mode is selected by the operation/setting-modeswitching unit 51 d, a function of adjusting the matching degreethreshold is allocated to the increase/decrease adjusting unit 51 h. Inthis way, on a screen that needs to be operated, an appropriate functionis automatically allocated to the increase/decrease adjusting unit 51 h,to which a plurality of functions are allocated, without selecting anyone of the functions in advance. It is possible to improve operabilityof the user.

Note that the function allocation for each of the operation modes is anexample. For example, in the setting mode, when the adjustment of theimage display magnification and the matching degree threshold isperformed, in a state in which a screen on which the adjustment of thedisplay magnification is possible (a magnification adjustment mode) anda screen on which the adjustment of the matching degree threshold ispossible (a threshold adjustment mode) are displayed, the respectivefunctions maybe selected with respect to the increase/decrease adjustingunit.

The increase/decrease adjusting unit 51 h is an increase/decreasebutton. A pair of up/down keys 44 is equivalent to the increase/decreaseadjusting unit 51 h. The up/down keys 44 include a ⇑ key 44 a, which isa switch on an up-side, and a ⇓ key 44 b, which is a switch on adown-side. The up/down keys 44 are used for adjustment of an increaseand a decrease, up and down movements, and the like. Note that, in theexample shown in FIG. 3A, the up/down keys 44 are configured by separatekeys, that is, the ⇑ key 44 a and the ⇓ key 44 b. However, the presentinvention is not limited to this configuration. The up/down keys 44 canbe integrated. The increase and the decrease can be performed by oneup/down key. Such an example is shown in FIG. 3B as a modification. Anup/down key 44B shown in the figure is configured in a tiltable seesawtype. It is possible to instruct an increase by tilting the up/down key44B upward and instruct a decrease by tilting the up/down key 44Bdownward.

The up/down keys 44 are vertically disposed side by side in this way.Therefore, the user can sensuously operate the up/down keys 44. That is,the user can increase a value by pressing the ⇑ key 44 a disposed in anupper part and reduce the value by pressing the ⇓ key 44 b disposed in alower part. Therefore, the user can sensuously operate the keys. It ispossible to reduce likelihood of erroneous operation. In general, theimage processing sensor includes a large number of components comparedwith a photoelectric sensor. A casing tends to be thick. Therefore, evenif the ⇑ key 44 a and the ⇓ key 44 b are vertically arranged in alongitudinally long shape, it is possible to secure width enough fordisposing the keys without increasing the casing in size. It is possibleto configure the exterior of the up/down keys 44 to match the shape ofthe up/down keys 44 with the function of the up/down keys 44.

When the display unit 43 having a rectangular shape is disposed on thesurface 40 a having a rectangular shape extending in one direction, itis reasonable in terms of space efficiency to dispose the display unit43 to match the longitudinal direction of the display unit 43 with thelongitudinal direction of the display surface 40 a. In this case, theup/down keys 44 are desirably disposed on a side surface in thelongitudinal direction of the display unit 43. When the up/down keys 44are disposed in upper and lower parts of the display unit 43, thethickness of the display surface 40 a increases, leading to an increasein the size of the casing of the image processing sensor. Therefore, thedisplay unit 43 and the up/down keys 44 are disposed side by side alongthe longitudinal direction of the display surface 40 a. This cancontribute to a decrease in the size of the image processing sensor.

Further, the up/down keys 44 are desirably disposed on the oppositesides across the display unit 43 rather than being collectively disposedon the same side with respect to the display unit 43 together withdetermination buttons and the like such as the SET key 42. Consequently,it is possible to reduce, by physically separating the up/down keys 44and the determination key, a risk of erroneous operation in which, afterthe display magnification and the matching degree threshold areincreased or reduced, in operation for sending an instruction fordetermination from the SET key 42, the SET key 42 is touched by mistakewhen the up/down keys 44 are operated halfway in the increase or thereduction and an unintended instruction of determination is performed.

Note that the up/down keys 44 are not always limited to be verticallydisposed side by side. For example, as shown in a modification in FIG.3C, up/down keys 44C may be horizontally disposed side by side. Inparticular, in the conventional photoelectric sensor, up/down keys areconfigured by a “<” key and a “>” key and horizontally disposed side byside in order to achieve a reduction in thickness. Therefore, in theimage processing sensor, the up/down buttons are disposed according tothe disposition example in the photoelectric sensor. Consequently, it iseasy to provide an operation feeling same as the operation feeling ofthe photoelectric sensor. It is easy even for a user of thephotoelectric sensor to introduce and operate the image processingsensor without discomfort.

In the examples shown in FIGS. 3A to 3C, the up/down keys 44, the BACKkey 45, the MODE key 46, and the like are disposed on the right side ofthe display unit 43. Since the keys requiring delicate operation aredisposed on the right side, it is possible to allow users considered tobe often right-handed to easily operate the keys with the right hands.

Further, the shapes of the keys are desirably differentiated from oneanother. Consequently, the user can distinguish types of the keys with atouch. Therefore, even when it is difficult to directly view the keysdisposed in a dark place or in deep positions, it is possible to operatethe keys with a tactile sense. For example, in the example shown in FIG.3A, in the up/down keys 44, the distal end on the upper side of the ⇑key 44 a is tapered and the distal end on the lower side of the ⇓ key 44b is tapered. The BACK key 45 and the MODE key 46 are horizontally longand vertically disposed side by side. On the other hand, the SET key 42is formed to be longitudinally long. In particular, by differentiatingthe shapes of the determination key from the shapes of the BACK key 45and the MODE key 46, it is possible to cause the user to surely performwork for pressing the determination key after the adjustment in theincrease/decrease adjusting unit 51 h.

Furthermore, in the increase/decrease adjusting unit 51 h, marks such asΔ and ∇ are displayed on key tops by stamping, printing, or the like.Consequently, it is possible to cause the user to visually grasp thatthe keys are keys for performing an increase and a decrease.

(Increase/Decrease Icon 61).

As shown in FIGS. 7 and 8 and the like referred to below, a display formof an increase/decrease icon 61 displayed on the display unit 43 can bechanged according to items adjustable by the increase/decrease adjustingunit 51 h. For example, as shown in FIG. 7, on a screen on which thematching degree threshold can be changed, the increase/decrease icon 61indicates that it is possible to display marks such as Δ and ∇ beside anumerical value together with a matching-degree-threshold display region62 in which a numerical value of the matching degree threshold currentlybeing set is displayed and increase or reduce the displayed value. Onthe other hand, as shown in FIGS. 8 and 9, on a screen on which an imageis displayed in an image display region PD, characters “ZOOM” and markssuch as Δ and ∇ beside the characters are displayed as theincrease/decrease icon 61 to indicate that it is possible to performzoom-in and zoom-out with the increase/decrease adjusting unit 51 h.

(Reversal Display Function)

Note that the display of an image, a numerical value, and the like onthe display unit 43 can be reversed as shown in FIG. 3D. Consequently,while flexibly changing a posture of the image processing sensor duringincorporation in a production line according to a draw-out direction orthe like of cables, it is possible to change the display itself on thedisplay unit 43 according to a direction visually recognized by the userand avoid a situation in which the display is reversed upside down andhard to be distinguished. Such a change in the display form on thedisplay unit 43 can be performed by a display control unit 58 fexplained below.

(Reversal Display Associated Increase/Decrease Function)

In this case, when the display of the display unit 43 is reversed, it ispossible to interchange the functions of the up/down keys 44 of theincrease/decrease adjusting unit 51 h and change the operation of theincrease and reduction to match the operation with a numerical value andthe top and the bottom of an image displayed on the display unit 43.Consequently, it is possible avoid an environment in which the increaseand the reduction have to be performed oppositely to arrows and the topand the bottom and erroneous operation easily occurs when the display isopposite as in the past. It is possible to avoid a setting mistake byperforming input operation, which is sensuously easy to understand, forincreasing a numerical value and an image in an upward direction andreducing the numerical value and the image in a downward direction.

(Determination-Result Display Lamp 41)

The determination-result display lamp 41 indicates, with lighting, aresult determined in the operation mode. For example, when anon-defective product is detected, the determination-result display lamp41 is lit in blue. When a defective product is detected, thedetermination-result display lamp 41 is lit in red. As such an outputdisplay lamp, a light emitting body such as an LED can be used. Alightemission color desirably can be changed. For example, a red LED and ablue LED can be provided. A multicolor LED with variable colors can beused.

The output-state display lamp 47 is a member for displaying a state ofan output. An LED and the like can be used as the output/state displaylamp 47. Details of the other members are explained below.

Note that the operation unit 51 and the display lamps can also bevirtually configured on a display besides being configured by physicalbuttons and lamps. For example, it is also possible to configure thedisplay surface with a touch panel, display the display unit, theoperation unit, and the display lamps as images on the display surface,and cause the display unit, the operation unit, and the display lamps tofunction as virtual buttons and lamps.

A connector unit 48, to which a cable is connected, is disposed in oneof the front surface or the rear surface among the surfaces configuringthe hexahedron shape of the casing 40. In the example shown in FIGS. 2Aand 2B and the like, the connector unit 48 having a cylindrical shape isprovided on the rear surface side (in the figures, the right side). Notethat, as shown in FIG. 1A, in the case of the image processing sensor ofthe separated type in which the head unit 2 and the controller unit 3are separated, a head-unit-side connector 3A for connecting the headunit 2 is provided on the front surface side.

(Cover Unit 3B)

A cover unit 3B may be provided on the display surface 40 a. Byproviding the cover unit 3B, it is possible to avoid a situation inwhich a hand or the like of the user touches the operation unit 51 bymistake and, for example, setting of the matching degree threshold isunintentionally changed. In the example shown in FIG. 1A, the cover unit3B covering the display unit 43 is provided to be capable of opening andclosing. In this example, the cover unit 3B is turnably coupled to oneend in the longitudinal direction of the display surface 40 a in a pivottype to be capable of opening and closing. By configuring the cover unit3B with a member having light transmissivity, it is possible to visuallyrecognize the display unit 43 even in a state in which the cover unit 3Bis closed. The cover unit 3B can be made of resin or the like.

A cover unit does not have to be provided. In FIG. 1B, an example of animage processing sensor in which a cover unit is not provided is shown.A key lock function may be imparted to the operation unit when the coverunit is not provided. When the key lock function is actuated, even ifthe user touches the operation unit, the operation unit does notrespond. It is possible to avoid, for example, an unintended change ofsetting. When performing operation, the user performs specific releaseoperation to release the key lock function. Such release operation canbe, for example, long-press of a specific key.

(Hardware Block Diagram)

A block diagram of the image processing sensor is shown in FIG. 4. Asshown in the figure, a hardware configuration of the image processingsensor mainly includes the imaging unit 21, the illuminating unit 26, apower supply unit 32, a main control unit 33, the display unit 43, andthe operation unit 51. Note that the figure shows a block diagram of theimage processing sensor of the integrated type shown in FIG. 1B. In thecase of the image processing sensor of the separated type shown in FIG.1A, the right side indicated by a broken line in FIG. 4 is equivalent tothe head unit 2 and the left side is equivalent to the controller unit3.

The power supply unit 32 includes a voltage conversion circuit forsupplying driving power to the units. In an example shown in FIG. 4, thepower supply unit 32 includes an illumination driving circuit 241 thatsupplies electric power to a light source of the illuminating unit 26and performs control of ON/OFF of lighting and a light amount of theilluminating unit 26. When the light source of the illuminating unit 26is an LED, the illumination driving circuit 241 is an LED drivercircuit. An external communication circuit 321 for performing datacommunication with the outside may be provided in the power supply unit32. The external communication circuit 321 functions as, for example, adetermination-result output unit that outputs, for example, adetermination result of a non-defective product and a defective productto the outside.

The main control unit 33 is a member for performing driving control ofthe imaging unit 21, image processing of an image obtained by theimaging unit 21, pass/fail determination, and the like. In the exampleshown in FIG. 4, the main control unit 33 is configured by a DSP 251, aMCU 331, a memory 252, and the like. The main control unit 33 includesan image/setting storing unit 54 for retaining a model image andsetting. The image/setting storing unit 54 is configured by a storagesuch as a semiconductor memory or a hard disk.

The operation unit 51 is a member for the user to perform various kindsof operation on the image processing sensor. Specifically, variousbuttons provided on the display surface 40 a of the casing 40 correspondto the operation unit 51. The function of the operation unit can beintegrated by the display unit by configuring the display unit with atouch panel.

(Functional Block Diagram)

Further, a detailed block diagram grasped in terms of the functions ofthe image processing sensor is shown in FIG. 5. As shown in the figure,the image processing sensor includes the operation unit 51, the imagingunit 21, the display unit 43, and the main control unit 33. Theoperation unit 51 is a member for receiving an operation instructionfrom the user and communicating the operation instruction to the maincontrol unit 33. The imaging unit 52 is a member for capturing an imageand passing the captured image to amain control unit 61. The displayunit 43 is a member for displaying a current sensor state and displayingcontent of an instruction to the user.

The main control unit 33 includes a setting managing unit 58, theimage/setting storing unit 54, a condition allocating unit 55, asetting-image processing unit 56, and an operation-image processing unit57. The setting managing unit 58 is a member for controlling theimage/setting storing unit 54, the condition allocating unit 55, thesetting-image processing unit 56, and the operation-image processingunit 57 on the basis of information inputs from the operation unit 51and the imaging unit 52 and performing display on the display unit 43.The image/setting storing unit 54 is a member for storing an image andsetting. The condition allocating unit 55 is a member for changing aregistered condition pattern and deducing an optimum registrationcondition. The setting-image processing unit 56 is a member forperforming image processing registration on the basis of an image tomake it possible to perform an evaluation of a target image. Theoperation-image processing unit 57 is a member for performing theevaluation of the target image and calculating a matching degree. Rolesof the blocks are explained below.

(Operation Unit 51)

The operation unit 51 is a member for receiving an operation instructionfrom the user and communicating the operation instruction to the maincontrol unit 33. In an example shown in FIG. 5, the operation unit 51includes a non-defective-product-image setting unit 51 a, adefective-product-image setting unit 51 b, a background-image settingunit 51 c, an operation/setting-mode switching unit 51 d, aresponse-time setting unit 51 e, a screen-display switching unit 51 g,an increase/decrease adjusting unit 51 h, a rotation-allowable-rangesetting unit 51 j, a cancellation instructing unit 51 i, and aregistration-mode switching unit 51 k.

(Non-Defective-Product-Image Setting Unit 51 a)

The non-defective-product-image setting unit 51 a is a member forreceiving an operation instruction for registering a non-defectiveproduct image from the user and communicating the operation instructionto the main control unit 61. An induction-display control unit 58 a ofthe setting managing unit 58 causes an operation-instruction displayunit 43 f to display on the display unit 43, a non-defective productimage registration instruction read out from aregistration-identification-instruction-information storing unit 54 h ofthe image/setting storing unit 54. At the same time, theinduction-display control unit 58 a causes a live-image display unit 43a to display, on the display unit 43, a live image captured by theimaging unit 52 and repeatedly updated. When the SET key 42 is depressedunder this situation, the non-defective-product-image setting unit 51 acommunicates the operation instruction to an image access unit of thesetting managing unit 58. The image access unit saves, on the basis ofthe operation instruction, a live image at the time when the SET key 42is depressed in a non-defective-product-image storing unit 541 a of theimage/setting storing unit 54 as a non-defective product image.

(Defective-Product-Image Setting Unit 51 b)

The defective-product-image setting unit 51 b is a member for receivingan operation instruction for registering a defective product image fromthe user and communicating the operation instruction to the main controlunit 61. The induction-display control unit 58 a of the setting managingunit 58 causes the operation-instruction display unit 43 f to display,on the display unit 43, a defective product image registrationinstruction read out from theregistration-identification-instruction-information storing unit 54 h ofthe image/setting storing unit 54. At the same time, theinduction-display control unit 58 a causes the live-image display unit43 a to display, on the display unit 43, a live image captured by theimaging unit 52 and repeatedly updated. When the SET key 42 is depressedunder this situation, the defective-product-image setting unit 51 bcommunicates the operation instruction to the image access unit of thesetting managing unit 58. The image access unit stores, on the basis ofthe operation instruction, a live image at the time when the SET key 42is depressed in a defective-product-image storing unit 542 a of theimage/setting storing unit 54 as a defective product image.

In setting of the defective product image, a still-image display unit 43b of the display unit 43 displays, via the image access unit of thesetting managing unit 58, on the display unit 43, the non-defectiveproduct image stored in the non-defective-product-image storing unit 541a of the image/setting storing unit 54. Consequently, in the setting ofthe defective product image, the user can set the defective productimage while comparing the defective product image with the non-defectiveproduct image.

(Background-Image Setting Unit 51 c)

The background-image setting unit 51 c is a member for receiving anoperation instruction for registering a background image from the userand communicating the operation instruction to the main control unit 61.The induction-display control unit 58 a of the setting managing unit 58causes the operation-instruction display unit 43 f to display on thedisplay unit 43, a background image registration instruction read outfrom the registration-identification-instruction-information storingunit 54 h of the image/setting storing unit 54. When the SET key 42 isdepressed under this situation, the background-image setting unit 51 ccommunicates the operation instruction to the image access unit of thesetting managing unit 58. The image access unit stores, on the basis ofthe operation instruction, a live image at the time when the SET key 42is depressed in a background-image storing unit 543 a of theimage/setting storing unit 54 as a background image.

(Registration-Mode Switching Unit 51 k)

The registration-mode switching unit 51 k is a member for switching andselecting a three-point teaching mode for transitioning a state among afirst registration screen, a second registration screen, and a thirdregistration screen with a screen transitioning unit 58 b explainedbelow and a two-point teaching mode for transitioning a state betweenthe first registration screen and the third registration screen with thescreen transitioning unit 58 b. Note that the registration-modeswitching unit 51 k may be capable of switching the two-point teachingmode and the three-point teaching mode to a one-point teaching mode foracquiring, for example, only one image and distinguishing presence orabsence of a target object of the image. As explained bellow, forexample, when the SET key 42 is short-pressed, as shown in FIG. 57B, aprogress bar for staring a setting mode of two-point teaching isdisplayed using the entire surface of the screen display 43 and theimage processing sensor is switched to the setting mode of the two-pointteaching. For example, when the SET key 42 is long-pressed, as shown inFIG. 57C, a progress bar for starting a setting mode of three-pointteaching is displayed using the entire surface of the screen display 43.The image processing sensor is switched to the setting mode of thethree-point teaching.

(Screen-Display Switching Unit 51 g)

The screen-display switching unit 51 g is a member for switching screendisplay by a first display form and screen display by a second displayform. The display control unit 58 f performs, on the display unit 43,various kinds of display in the first display form or the second displayform switched by the screen-display switching unit 51 g. Note that thescreen display set as a switching target by the screen-display switchingunit 51 g may be, for example, third to fifth display forms besides thefirst display form and the second display form and is not limited tothese display forms.

(Increase/Decrease Adjusting Unit 51 h)

The increase/decrease adjusting unit 51 h is a member for changingdisplay magnification of an image displayed on the display unit. Asexplained above, the increase/decrease adjusting unit 51 h can also beused as a member for adjusting the matching degree threshold. Theincrease/decrease adjusting unit 51 h is configured by a pair of membersof the switch on the up-side and the switch on the down-side.

(Rotation-Allowable-Range Setting Unit 51 j)

The rotation-allowable-range setting unit 51 j is a member for setting arotation allowable parameter indicating a rotation allowable rangereferred to in image posture positioning processing included inpredetermined image processing. The rotation-allowable-range settingunit 51 j can be used as the increase/decrease adjusting unit 51 h aswell. In the example of the display surface 40 a shown in FIG. 3A andthe like, functions of the rotation-allowable-range setting unit 51 jare allocated to a ⇑ key and a ⇓ key.

(Cancellation Instructing Unit 51 i)

The cancellation instructing unit 51 i is a member for performing acancellation instruction according to user operation. In the example ofthe display surface 40 a shown in FIG. 3A and the like, the back key 45corresponds to the cancellation instructing unit 51 i.

(Specific Example of the Operation Unit 51)

In the image processing sensor shown in FIG. 3A, the operation unit 51is configured by, as hardware, the SET key 42, the BACK key 45, the MODEkey 46, and the like. By button operation of the SET key 42, accordingto operation states, that is, display screens of the display unit 43,various operation instructions corresponding to the operation states aregiven to the main control unit 33. For example, on the firstregistration screen shown in FIG. 9 explained below, when the SET key42, which is the operation unit 51, is depressed, a non-defectiveproduct image registration instruction for registering, as anon-defective product image, a live image displayed in the image displayregion PD at this point in time (real time display, display content ofwhich is updated at any time) is given. On the second registrationscreen shown in FIG. 13, when the SET key 42 is depressed, a backgroundimage registration instruction for registering, as a background image, astill image displayed in the image display region PD is given.

Further, the operation unit 51 can also give a plurality of operationinstructions. For example, on the first registration screen shown inFIG. 9, when the SET key 42 is depressed, in addition to thenon-defective product image registration instruction for registering thenon-defective product image, a screen transition instruction fortransitioning the display of the display unit 43 from the firstregistration screen to the second registration screen is instructed tothe main control unit 33. By performing such allocation of the pluralityof operation instruction on the operation unit 51, operability of theuser is improved. That is, by executing a plurality of operationsaccording to one operation of the operation unit 51, that is, thedepression of the SET 42, it is possible to obtain an advantage that theuser can smoothly perform registration work without being aware of, forexample, switching of the registration screen.

In this embodiment, the SET key 42 is used for the registration of thenon-defective product image, the defective product image, and thebackground image. The ⇑ key 44 a and the ⇓ key 44 b are used for thematching degree threshold adjustment, the magnification setting, theitem selection, and the like. The MODE key 46 is used for the displayswitching and the switching of the various kinds of setting. Examples ofthe switching of the setting include changes of a response time, arotation allowable angle, and a registration mode.

(Imaging Unit 21)

The imaging unit 21 is a member for capturing an image and passing thecaptured image to the main control unit 33. In this embodiment, a CMOSis used as an imaging element of the imaging unit 21. As the imagingelement, other imaging elements such as a CCD can also be used. A modefor acquiring an image with a method of, for example, reading outalready-captured image data from an external storage device ortransferring an image captured by an external imaging element is alsoincluded in the imaging unit referred to in this specification. Animage-group acquiring unit 52 a is provided in order to control theoperation of the imaging unit. The image-group acquiring unit 52 a canacquire a plurality of non-defective product candidate images, aplurality of defective product candidate images, and a plurality ofbackground candidate images using the imaging unit (details areexplained below).

(Display Unit 43)

The display unit 43 is a member for displaying a current sensor stateand displaying content of an instruction to the user. As the displayunit 43, besides an organic EL element (OLED), a liquid crystal (LCD)and the like can be used. Alternatively, besides incorporating thedisplay unit 43 in the display surface 40 a of the casing 40 as shown inFIG. 3A and the like, the display unit may be externally attached. Avideo signal can be output to such an external display device.

(Setting Managing Unit 58)

Referring back to FIG. 5, the setting managing unit 58 includes thedisplay control unit 58 f, the induction-display control unit 58 a, animage registering unit 58 g, the screen transitioning unit 58 b, animage access unit 58 c, a matching-degree-statistical-value access unit58 d, and a bank-switching control unit 58 e.

The image/setting storing unit 54 includes an image storing unit 54 i, asetting saving unit 54 d, a matching-degree-statistical-value storingunit 54 e, a bank-setting storing unit 54 f, a threshold (first andsecond) storing unit 54 g, and aregistration-identification-instruction-information storing unit 54 h.The image storing unit 54 i includes a still-image storing unit 54 a, alive-image storing unit 54 b, and amatching-degree-statistical-time-image storing unit 54 c. Thestill-image storing unit 54 a includes a non-defective-product-imagestoring unit 541 a, a defective-product-image storing unit 542 a, and abackground-image storing unit 543 a.

The condition allocating unit 55 includes an imaging-conditionallocating unit 55 d, an image-compression-degree setting unit 55 h, andan image-processing-condition allocating unit 55 i. Theimaging-condition allocating unit 55 d includes a brightness-conditionallocating unit 55 e. The brightness-condition allocating unit 55 eincludes a brightness-condition-candidate setting unit 55 f and abrightness-condition selecting unit 55 g.

The setting-image processing unit 56 includes a differential-imagegenerating unit 56 a, a feature-value extracting unit 56 b, a thresholdcalculating unit 56 c, and an image compressing unit 56 d.

The operation-image processing unit 57 includes a feature-valueextracting unit 57 a, a matching-degree calculating unit 57 c, amatching-degree-statistical-value calculating unit 57 e, and a pass/faildetermining unit 57 d. A relation among the units is explained below.

(Display Control Unit 58 f)

The display control unit 58 f is a member for controlling display of animage, a text, and the like on the display unit. For example, thedisplay control unit 58 f causes the display unit 43 to display anon-defective product image as a live image on the first registrationscreen, causes the display unit 43 to display a defective product imageas a live image on the second registration screen, and causes thedisplay unit 43 to display a background image as a live image on thethird registration screen.

(Induction-Display Control Unit 58 a)

The display control unit 58 f includes the induction-display controlunit 58 a. As explained above, the induction-display control unit 58 acauses the operation-instruction display unit 43 f to display, on thedisplay unit 43, a non-defective product image registration instructionread out from the registration-identification-instruction-informationstoring unit 54 h of the image/setting storing unit 54. At the sametime, induction-display control unit 58 a causes the live-image displayunit 43 a to display, on the display unit 43, a live image captured bythe imaging unit 52 and repeatedly updated.

(Image Registering Unit 58 g)

The image registering unit 58 g is a member for registering an imagecaptured by the imaging unit. In the setting mode, the image registeringunit 58 g also plays a function of retaining, as candidate images, aplurality of image groups acquired by the image-group acquiring unit andregistering images selected out of the candidate images. For example,the image registering unit 58 g can also temporarily register aplurality of non-defective product image as a non-defective productimage group, temporarily register a plurality of background images as abackground image group, or temporarily register a plurality of defectiveproduct images as a defective product image group. The registered imagesare retained in the image/setting storing unit 54. In this sense, theimage registering function is considered to be realized by the imageregistering unit 58 g and the image/setting storing unit 54. However,the image registering function can also be realized by only the imageregistering unit or only the image/setting storing unit. For example, amemory for retaining images can be provided on the setting managing unitside or a control unit that performs image registration processing canbe provided on the image/setting storing unit side.

Display examples of the display unit 43 are shown in FIGS. 7 to 11. Inthe display unit 43 shown in the figures, a display region is dividedinto two and an image display region PD for causing the display unit 43to display an image and an explanation display region ED for displayingexplanation are provided. In the example shown in FIG. 9 and the like,the image display region PD is provided on the left side of thehorizontally long display unit 43 and the explanation display region EDis provided on the right side. Naturally, the display region can bedisplayed in various modes for interchanging the left and the right,forming the display region vertically long and dividing the displayregion vertically into two.

(Registration Induction Information)

The display control unit 58 f can cause the .display unit 43 to displaya live image and a still image in the image display region PD. Thedisplay control unit 58 f can cause the display unit 43 to displaycharacters and figures for explanation and guidance in the explanationdisplay region ED. Specifically, the display control unit 58 f can causethe display unit 43 to display an image displayed in the image displayregion PD and display, as characters, figures, and the like, a procedurethat should be performed according to the image. The display controlunit 58 f may cause the display unit 43 to display characters andfigures for explanation as a moving image. For example, the displaycontrol unit 58 f causes, with the induction-display control unit 58 aof the display control unit 58 f, the display unit 43 to displayregistration induction information in the explanation display region ED.The registration induction information is information for inducing theuser to register an image. For example, character information and imageinformation can be used as the registration induction information.Besides a still image, a moving image may be used as the imageinformation. The character information and the image information canalso be combined. The registration^(,) induction information includesfirst registration induction information for inducing registration ofone image on the first registration screen and second registrationinduction information for inducing registration of the other image onthe second registration screen. Details of the registration inductioninformation are explained below.

(Threshold Calculating Unit 56 c)

The threshold calculating unit 56 c is a member for calculating amatching degree threshold with respect to a matching degree indicating adegree of matching of features values of a first image including aninspection target object that should be distinguished as a non-defectiveproduct displayed on the display unit 43 and a second image notincluding the inspection target object that should be distinguished asthe non-defective product displayed on the display unit 43. The firstimage can be, for example, a non-defective product image and the secondimage can be, for example, a background image or a defective productimage.

(Screen Transitioning Unit 58 b)

The screen transitioning unit 58 b is a member for transitioning thefirst registration screen for registering one image of the first imageand the second image as an image used for the matching degree thresholdcalculation by the threshold calculating unit 56 c to the secondregistration screen for registering the other image used for thematching degree threshold calculation by the threshold calculating unit56 c.

(Display Control Unit 58 f)

The display control unit 58 f is a member for controlling displaycontent on the display unit 43. The display control unit 58 f includesthe induction-display control unit 58 a.

(Induction-Display Control Unit 58 a)

The induction-display control unit 58 a causes the display unit 43 todisplay, as a live image, one image captured by the imaging unit 21 onthe first registration screen. Further, the induction-display controlunit 58 a causes the display unit 43 to display the first registrationinduction information for inducing registration of the one image. Theinduction control unit causes the display unit 43 to display the liveimage in the image display region PD of the display unit 43 and causesthe display unit 43 to display the first registration inductioninformation in the explanation display region ED.

The induction-display control unit 58 a can also cause the display unit43 to display the other image as a live image in the image displayregion PD on the second registration screen and cause the display unit43 to display the second registration induction information for inducingregistration of the other image in the explanation display region ED.

(Image/Setting Storing Unit 54)

The image/setting storing unit 54 is a member for storing an image andsetting. As the image/setting storing unit 54, an internal SRAM, anexternal Flash ROM, and the like can be used. For example, since theregistration induction information needs to be always stored, a FlashROM or the like, which is a nonvolatile memory, is used as theregistration-identification-instruction-information storing unit 54 hfor storing the registration induction information. Note that theimage/setting storing unit 54 may be provided as a separate device foreach of data. A volatile or nonvolatile memory may be used as theimage/setting storing unit 54. Each of data may be saved in separatemember or separate device.

(Still-Image Storing Unit 54 a)

The still-image storing unit 54 a is a member for storing a registeredimage. The still-image storing unit 54 a saves the live image, which issaved in the image/setting storing unit 54, in the still-image storingunit 54 a (the non-defective-product-image storing unit 541 a, thedefective-product-image storing unit 542 a, and the background-imagestoring unit 543 a) of the image/setting storing unit 54 at timing of aninput or timing immediately after the input via thenon-defective-product-image setting unit 51 a, thedefective-product-image setting unit 51 b, and the background-imagesetting unit 51 c in the operation unit 51.

(Live-Image Storing Unit 54 b)

The live-image storing unit 54 b is a member for storing a live image.The live-image storing unit 54 b always saves an image obtained from theimaging unit 52 in the image/setting storing unit 54. The live image isrequested to move at extremely high speed to be repeatedly updated andtemporarily stored. Therefore, an SRAM is used as the live-image storingunit 54 b for storing the live image.

(Matching-Degree-Statistical-Time-Image Storing Unit 54 c)

The matching-degree-statistical-time-image storing unit 54 c is a memberfor storing, as matching degree statistical time image, a live image atthe time when matching degree statistical values, which are allstatistical values of a matching degree such as an ON time peak maximumvalue including a maximum value and a minimum value of the matchingdegree, are calculated. The matching degree statistical time image canbe configured to be read out from thematching-degree-statistical-time-image storing unit 54 c and displayedinstead of a live image in a second representation form and a fourthrepresentation form or representation forms of modifications of thesecond representation form and the fourth representation form.

(Setting Saving Unit 54 d)

The setting saving unit 54 d is a member for saving various settingcontent.

(Matching-Degree-Statistical-Value Storing Unit 54 e)

The matching-degree-statistical-value storing unit 54 e is a member forstoring matching degree statistical values, which are all statisticalvalues of a matching degree such as an ON time peak maximum valueincluding a maximum value and a minimum value of the matching degree.

(Bank-Setting Storing Unit 54 f)

The bank-setting storing unit 54 f is a member for storing a pluralityof settings switched by the bank switching unit 511 and read out. Whenthe MODE button 64 and the up/down keys 44 are simultaneously depressed,BNK is switched among BNK1 to BNK4. The BNK is stored in thebank-setting storing unit 54 f in association with BNK displayed on thedisplay unit 43.

(Threshold (First and Second) Storing Unit 54 g),

The threshold (first and second) storing unit 54 g is a member forstoring a first threshold and a second threshold compared with amatching degree of an input image when an output-channel setting unit 51m sets a channel for outputting a first determination result and asecond determination result.

(Registration-Identification-Instruction-Information Storing Unit 54 h)

The registration-identification-instruction-information storing unit 54h is a member for storing registration induction information forinducting registration of images that should be registered such as anon-defective product image, a defective product image, and a backgroundimage. The registration induction information is displayed in theexplanation display region ED by the operation-instruction display unit43 f under the management by the induction-display control unit 58 a. Anonvolatile memory, a semiconductor memory, a hard disk, and the likecan be used as the registration-identification-instruction-image storingunit 54 h.

(Condition Allocating Unit 55)

The condition allocating unit 55 is a member for performing adjustmentfor changing registration setting conditions and determining optimumregistration setting conditions. Specifically, in the setting mode, thecondition allocating unit sets, according to a response time given fromthe response-time setting unit 51 e, candidates of a plurality ofdifferent registration setting conditions that can be set, performs anevaluation on candidate images obtained under the registration settingcondition candidates, registers a candidate image suitable for pass/faildetermination as a registration image, and retains the registrationsetting conditions at this point such that an image is captured underthe registration setting conditions in the operation mode to perform thepass/fail determination.

The condition allocating unit 55 includes the imaging-conditionallocating unit 55 d, the image-compression-degree setting unit 55 h,and the image-processing-condition allocating unit 55 i. Theimaging-condition allocating unit 55 d is capable of adjusting imagingconditions for an image such that predetermined image processing forperforming the pass/fail determination can be performed within theresponse time set by the response-time setting unit. Theimaging-condition allocating unit 55 d includes the brightness-conditionallocating unit 55 e capable of adjusting conditions concerningbrightness of an image, that is, parameters of brightness. Examples ofthe parameters of brightness include an exposure time and illuminationintensity. The brightness-condition allocating unit 55 e furtherincludes the brightness-condition-candidate setting unit 55 f and thebrightness-condition selecting unit 55 g.

(Brightness-Condition-Candidate Setting Unit 55 f)

The brightness-condition-candidate setting unit 55 f is a member forsetting each of a plurality of brightness conditions as a brightnesscondition candidate such that a determination result is output withinthe give response time.

(Brightness-Condition Selecting Unit 55 g)

The brightness-condition selecting unit 55 g is a member for selectingbrightness conditions out of a plurality of brightness conditioncandidates according to selection conditions on the basis of a matchingdegree calculated for each of the plurality of brightness conditioncandidates by the matching-degree calculating unit 57 c.

The condition allocating unit 55 explained above determines theevaluation methods for cutting out, respectively from, for example, anon-defective product image and a background image and a defectiveproduct image and the background image, a non-defective product imagefrom which a background is removed and a defective product image fromwhich the background is removed and deducing, on the basis of the imagesfrom which the background is removed, optimum registration conditionsfor distinguishing a non-defective product and a defective product. Forexample, the image-compression-degree setting unit 55 h changes theresolution of an image, the image-processing-condition allocating unit55 i changes a processing flow of image processing, and thebrightness-condition allocating unit 55 e changes brightness incapturing an image. Alternatively, the condition allocating unit 55 mayinclude a feature-value-extraction-processing allocating unit thatchanges an extraction method for internal feature values. In this way,the condition allocating unit 55 changes a registration conditionpattern and sets, as an optimum registration condition, a registrationcondition pattern under which a matching degree calculated by thethreshold calculating unit 56 c of the setting-image processing unit 56is optimum. Note that this functional block may be assumed by, forexample, the setting managing unit 58.

(Setting-Image Processing Unit 56)

The setting-image processing unit 56 is a member for performing imageprocessing registration on the basis of an image to make it possible toperform an evaluation of a target image. The setting-image processingunit 56 performs registration of an image processing algorithm on thebasis of at least one image among a non-defective product image, adefective product image, and a background image given to thesetting-image processing unit 56, determines weight parameters ofinternal feature values, performs an evaluation of a target image in theoperation-image processing unit 57 during registration processing,calculates a matching degree, and calculates a threshold fordistinguishing the non-defective product image and the defective productimage. Note that, during the registration processing in the settingmode, operation is sometimes performed to calculate a matching degreethreshold. Therefore, in FIG. 5, the setting-image processing unit 56 isshown to be connected the operation-image processing unit 57.

(Differential-Image Generating Unit 56 a)

The differential-image generating unit 56 a is a member for excluding abackground image from a non-defective product image and generating asimple differential image in which only non-defective work is extractedor excluding the background image from a defective product image andgenerating a simple differential image in which only defective work isextracted. In the differential images, corresponding pixels of the twoimages are subtracted from each other to obtain a difference. However,“differential” in this specification is not limited to simpledifferential processing for subtracting the corresponding pixels fromeach other. For example, “differential” used in a meaning includingexcluding an element common to a background to specify a work region.

(Feature-Value Extracting Unit 56 b)

The feature-value extracting unit 56 b is a member for extractingfeature values from image data. The feature values are called featurepoints or simply called features or the like as well. Examples of thefeature values include a contour (an edge), the number of edge pixels,and a luminance average/dispersion. As an algorithm for extracting suchfeature values from the image data, for example, for an edge feature, aknown algorithm such as a Sobel filter can be used.

(Threshold Calculating Unit 56 c)

The threshold calculating unit 56 c is a member for calculating athreshold with respect to a matching degree indicating a degree offeature matching between a non-defective product image including aninspection target object that should be distinguished as a non-defectiveproduct or an image serving as a reference of pass/fail determination(corresponding to an example of the “first image” in claims) generatedon the basis of the non-defective product image displayed on the displayunit 43 and a background image (corresponding to an example of the“second image” in claims) or a defective product image (corresponding toanother example of the “second image” in claims) not including theinspection target object that should be distinguished as thenon-defective product displayed on the display unit 43. The thresholdcalculating unit 56 c automatically calculates the threshold withrespect to the matching degree indicating the degree of feature matchingbetween the non-defective product image and the background image or thedefective product image. When teaching is performed from two points ofthe non-defective product image and the background image, the thresholdcalculating unit 56 c respectively calculates feature values of thenon-defective product image and the background image and draws athreshold between the feature values. When teaching is performed fromthree points of the non-defective product image, the defective productimage, and the background image, the threshold calculating unit 56 crespectively cuts out, from the non-defective product image and thebackground image and the defective product image and the backgroundimage, a non-defective product image from which a background is removedand a defective product image from which the background is removed,calculates feature values of the non-defective product image and thedefective product image from which the background is removed, and drawsa threshold between the feature values.

(Image Compressing Unit 56 d)

The image compressing unit 56 d is a member for compressing an image toreduce the resolution of the image. As an image compressing method,known methods such as a Lanczos method, an average pixel method, and abicubic method can be used. The image compressing unit 56 d alsofunctions to compress, on the basis of a given response time, an inputimage of a compression target to be a data size processable bypredetermined image processing within the response time.

(Operation-Image Processing Init 57)

The operation-image processing unit 57 is a member for performing theevaluation of the target image and calculating a matching degree. In astate in which the image processing algorithm is registered by thesetting-image processing unit 56, the operation-image processing unit 57causes the registered image processing algorithm to operate on anevaluation target image and calculates a matching degree of an operationimage with a non-defective product image. The operation-image processingunit 57 compares the matching degree calculated with respect to theoperation image and the threshold calculated by the thresholdcalculating unit 56 c of the setting-image processing unit 56 anddetermines whether the work WK is a non-defective product or a defectiveproduct.

(Feature-Value Extracting Unit 57 a)

The feature-value extracting unit 57 a is a member for extractingfeature values from image data. The feature values are called featurepoints or simply called features or the like as well. Examples of thefeature values include a contour (an edge), the number of edge pixels,and a luminance average/dispersion. As an algorithm for extracting suchfeature values from the image data, for example, for an edge feature, aknown algorithm such as a Sobel filter can be used. Note that thefeature-value extracting unit 57 a can also be used in common with thefeature-value extracting unit 56 b of the setting-image processing unit56 explained below. In this case, the feature-value extracting unit 57 acan calculate feature values and send the feature values to thesetting-image processing unit 56 during registration. Conversely, thefeature-value extracting unit 56 b of the setting-image processing unit56 can calculate feature values and send the feature values to theoperation-image processing unit 57 during operation. Alternatively, thesetting-image processing unit 56 and the operation-image processing unit57 may be integrated.

(Matching-Degree Calculating Init 57 c)

The matching-degree calculating unit 57 c is a member for performing anevaluation of a target image and calculating a matching degree. Thematching degree means a degree of matching with a non-defective productimage. For example, when a matching degree of a target image, which isthe non-defective product image, is represented as 100%, if a degree ofmatching of a background image and the non-defective product image is70%, a matching degree of the background image is 70%. 85% in the middleof the matching degree of the non-defective product image and thematching degree of the background image is set as a threshold. Thematching degree may be calculated as a ratio in this way. Alternatively,scores may be distributed for each of feature values. Rather than adegree, a total value of the scores distributed for each of the featurevalues may be set as the matching degree. In the embodiment explainedabove, the matching degree is defined as the degree of matching with thenon-defective product image or scored values of the feature values.However, the matching degree may be defined as a degree of matching withthe defective product image or can be defined as a degree of matchingwith a target image desired by the user by selecting the first image asappropriate.

(Matching-Degree-Statistical-Value Calculating Unit 57 e)

The matching-degree-statistical-value calculating unit 57 e is a memberfor calculating a matching degree statistical value of the matchingdegree, which is calculated by the matching-degree calculating unit 57c, from an operation start time or from hold clear of the matchingdegree statistical value. The matching-degree-statistical-valuecalculating unit 57 e calculates an ON time peak value, ON time peakmaximum/minimum values, an OFF time bottom value, and OFF time bottommaximum/minimum values tied to a maximum value, a minimum value, and asetting threshold of the matching degree. If a matching degree updated,for example, at every 3 ms exceeds a maximum value in the past, thematching-degree-statistical-value calculating unit 57 e calculates avalue of the matching degree as a maximum matching degree. Similarly, ifthe matching degree updated, for example, at every 3 ms falls below aminimum value in the past, the matching-degree-statistical-valuecalculating unit 57 e calculates a value of the matching degree at thistime as a minimum matching degree.

At an ON time when a matching degree exceeds a threshold and aninspection target object is distinguished as a non-defective product andat an end time of a current sampling period, if an ON time peak value inthe sampling period exceeds an ON time peak maximum value in the past,the matching-degree-statistical-value calculating unit 57 e calculatesthe ON time peak value as an ON time peak maximum value. If the ON timepeak value in the sampling period falls below an ON time peak minimumvalue in the past, the matching-degree-statistical-value calculatingunit 57 e calculates the ON time peak value as an ON time peak minimumvalue. Furthermore, at an OFF time when the matching degree falls belowthe threshold and the inspection target object is distinguished as adefective product and at the end time of the current sampling period, ifan OFF time bottom maximum value in the sampling period exceeds an OFFtime bottom maximum value in the past, thematching-degree-statistical-value calculating unit 57 e calculates theOFF time bottom value as an OFF time bottom maximum value. If the OFFtime bottom value in the sampling period falls below the OFF time bottommaximum value in the past, the matching-degree-statistical-valuecalculating unit 57 e calculates the OFF time bottom value as an OFFtime bottom minimum value.

(Setting Managing Unit 58)

The setting managing unit 58 is a member for supervising the functionalblocks. The setting managing unit 58 controls the image/setting storingunit 54, the condition allocating unit 55, the setting-image processingunit 56, and the operation-image processing unit 57 on the basis ofinformation input by the operation unit 51 and the imaging unit 52 anddisplays a necessary image and information on the display unit 43. Forexample, in the setting mode, in a live image setting waiting state, thesetting managing unit 58 always saves an image obtained from the imagingunit 21 in a memory (volatile or nonvolatile). At timing when an imageregistration command is received from the operation unit 51, the settingmanaging unit 58 registers, as a non-defective product image, adefective product image, or a background image, a live image saved inthe memory. Alternatively, the setting managing unit 58 registers a liveimage immediately after the operation unit 51 is depressed as thenon-defective product image, the defective product image, or thebackground image not through image data saved in the memory. The settingmanaging unit 58 transfers the registered image to the conditionallocating unit 55 and causes the display unit 43 to display aregistration result. On the other hand, in the operation mode, thesetting managing unit 58 receives a live image of an evaluation targetfrom the imaging unit 21, sends the live image to the operation-imageprocessing unit 57, and causes the display unit 43 to display anevaluation result of the operation-image processing unit 57.

During the setting, the setting managing unit 58 always saves an imageobtained from the imaging unit 52 in the image/setting storing unit 54.At timing of an input via the non-defective-product-image setting unit51 a, the defective-product-image setting unit 51 b, and thebackground-image setting unit 51 c in the operation unit 51 or at timingimmediately after the input, the setting managing unit 58 saves the liveimage, which is saved in the image/setting storing unit 54, in thestill-image storing unit 54 a (the non-defective-product-image storingunit 541 a, the defective-product-image storing unit 542 a, and thebackground-image storing unit 543 a) of the image/setting storing unit54 and displays the live image on the still-image display unit 43 b ofthe display unit 43 as a registration result.

During the operation, the setting managing unit 58 outputs an imageobtained from the imaging unit 52 to the operation-image processing unit57 as a target image and displays an evaluation result by theoperation-image processing unit 57 on a determination-result displayunit of the display unit 43.

(Display Control Unit 58 f)

The display control unit 58 f is a member for controlling displaycontent in the display unit 43 as explained above. The display controlunit 58 f may include the induction-display control unit 58 a. Thedisplay control unit 58 f performs, on the display unit 43, variouskinds of display in the first to fifth display forms switched by thescreen-display switching unit 51 g.

(Induction-Display Control Unit 58 a)

The induction-display control unit 58 a is a member for controllingdisplay content in the display unit 43. The induction-display controlunit 58 a may include the screen transitioning unit 58 b. A paralleldisplay function of a live image and a non-defective product imageregistered last time on the second registration screen is imparted tothe image access unit 58 c. However, the induction-display control unit58 a may assume the function.

(Screen Transitioning Unit 58 b)

The screen transitioning unit 58 b is a member for transitioning thefirst registration screen for registering one image of the first imageand the second image as an image used for the threshold calculation bythe threshold calculating unit 56 c to the second registration screenfor registering the other image used for the threshold calculation bythe threshold calculating unit 56 c. The screen transitioning unit 58 bcauses the display unit 43 to display, as a live image, one imagecaptured by the imaging unit 52 on the first registration screen.Further, the screen transitioning unit 58 b causes the display unit 43to display the first registration induction information for inducingregistration of the one image. The screen transitioning unit 58 b causesthe display unit 43 to display the live image in the image displayregion PD of the display unit and causes the display unit 43 to displaythe first registration induction information in the explanation displayregion ED.

On the second registration screen as well, the screen transitioning unit58 b can cause the display unit 43 to display the other image in theimage display region PD as the live image and cause the display unit 43to display the second registration induction information for inducingregistration of the other image in the explanation display region ED.

(Image Access Unit 58 c)

The image access unit 58 c is a member for performing saving, deletion,and readout of a non-defective product image, a defective product image,a background image, a live image, a matching degree statistical timeimage, and the like. For example, on the second registration screenduring teaching, the image access unit 58 c causes the display unit 43to display the live image on the left side of the display unit 43 viathe live-image display unit 43 a and causes the display unit 43 todisplay the non-defective product image registered last time on theright side via the still-image display unit 43 b. Consequently, the usercan register the defective product image, for example, while viewing theregistered image of the non-defective product image. Therefore, it ispossible to prevent unintended registration.

On the first registration screen shown in FIG. 9 in the case of theteaching of the two points of the non-defective product image and thebackground image, when the SET key 42, which is the operation unit 51,is depressed, the image access unit 58 c saves the live image displayedin the image display region PD at this point in time in thenon-defective-product-image storing unit 541 a as the non-defectiveproduct image. On the second registration screen shown in FIG. 8, whenthe SET key 42 is depressed, the image access unit 58 c saves the liveimage displayed in the image display region PD in the background-imagestoring unit 543 a as the background image.

On the second registration screen shown in FIG. 17 in the case of theteaching of the three points of the non-defective product image, thedefective product image, and the background image, when the SET key 42is depressed, the image access unit 58 c saves the live image displayedin the image display region PD in the defective-product-image storingunit 542 a as the defective product image. On the third registrationscreen shown in FIG. 18, when the SET key 42 is depressed, the imageaccess unit 58 c saves the live image displayed in the image displayregion PD in the background-image storing unit 543 a as the backgroundimage.

(Matching-Degree-Statistical-Value Access Unit 58 d)

The matching-degree-statistical-value access unit 58 d is a member forperforming saving, deletion, and readout of a matching degreestatistical value. For example, during the operation, thematching-degree-statistical-value access unit 58 d causes thematching-degree-statistical-value calculating unit 57 e to calculate amatching degree statistical value, saves the matching degree statisticalvalue in the matching-degree-statistical-value storing unit 54 e, readsout the matching degree statistical value saved in thematching-degree-statistical-value storing unit 54 e, and causes thedisplay unit 43 to display the matching degree statistical value.

(Bank-Switching Control Unit 58 e)

The bank-switching control unit 58 e is a member for enabling aplurality of BNKs to be switched, causing the bank-setting storing unit54 f to store setting in association with BNK, reading out the settingin association with the BNK, and performing control for performingoperation in the read-out setting.

(Registration of an Image in the Setting Mode)

In the image processing sensor, examples of a method of registering animage in the setting mode include the following four methods.

1. Three-Point Registration

In three-point registration, a non-defective product image, a defectiveproduct image, and a background image are registered. An object of thethree-point registration is identification of a non-defective productand a defective product. When the image processing sensor is switched tothe operation mode after the three-point registration is performed, amatching degree for evaluating how close an input image is to thenon-defective product image is calculated.

2. Two-Point Registration (the Non-Defective Product Image and theDefective Product Image are Registered)

In the two-point registration, the non-defective product image and thedefective product image are registered. An object of the two-pointregistration is also identification of a non-defective product and adefective product. When the image processing sensor is switched to theoperation mode after the two-point registration is performed, a matchingdegree for evaluating how close an input image is to the non-defectiveproduct image is calculated.

Note that a difference between the two-point registration and thethree-point registration is that possibility of work specifying isdifferent depending on presence or absence of the background image. Thatis, in a situation in which the background image is not registered,since the differential processing cannot be performed, a non-defectivework and a defective work cannot be satisfactorily specified. Since workcannot be specified, information concerning a non-defective product/adefective product during registration is “a non-defective productincluding a background” and “a defective product including abackground”. Since the background and a work region cannot beidentified, when a background included in the non-defective productimage and a background included in the defective product image aredifferent (e.g., the sizes of the non-defective work and the defectivework are different), identification is attempted according to adifference between the backgrounds that should originally be excludedfrom an evaluation target, leading to erroneous detection.

Not only during the registration but also during the operation, since anon-defective product or a defective product cannot be cut out from aninput image, pass/fail determination is performed according to workincluding a background. In this case, even when the background unrelatedto the non-defective product and the defective product changes, amatching degree changes on the basis of the change. In this way, sincean unstable element (i.e., the background) is included in theidentification focused only on the non-defective product and thedefective product, a best identification result cannot be expected.Therefore, a difference occurs in detection performance according topresence or absence of the background image. The three-pointregistration capable of specifying work is expected to have higherdetermination performance.

3. Two-Point Registration (the Non-Defective Product Image and theBackground Image are Registered)

On the other hand, as another kind of the two-point registration, anexample is assumed in which the non-defective product image isregistered and the background image is registered instead of thedefective image. An object of the two-point registration is distinctionof presence or absence of non-defective work. When the image processingsensor is switched to the operation mode after the two-pointregistration is performed, a probability of presence of seeminglynon-defective work is calculated at a matching degree of 0 to 100%.

The two-point registration for registering the non-defective productimage and the background image can also be used for the identificationuse. In this case, since the non-defective work is specified duringregistration, it is possible to perform identification operation byidentifying whether the non-defective work is present on the operationscreen. However, since a defective work is absent, a matching degreeneeds to be evaluated in the entire non-defective work. In this case, ifwork, which is partially chipped non-defective work, is assumed as thedefective work, the matching degree has to be changed on the basis ofthe size of the chip. A large matching degree difference cannot becalculated with respect to a small chip. It is likely that distinctionsensitivity of a non-defective product/a defective product isinsufficient.

On the other hand, in the three-point registration, since thenon-defective work and the defective work are registered, a regionincluding a difference can be specified in advance. Therefore,irrespective of work and the magnitude of a difference, by performingmatching degree determination in a portion including the difference, itis possible to calculate a large matching degree difference even withrespect to a small chip. Therefore, a difference occurs in theidentification performance according to presence of absence of thedefective product image. The three-point registration capable ofspecifying a defective produce is expected to have higher determinationperformance. According to the registration of the plurality of images, ahigh identification property and high stability are realized comparedwith a method of performing registration processing with one image as inthe past.

4. One-Point Registration (the Non-Defective Product Image or theBackground Image is Registered)

In one-point registration, the non-defective product image or thebackground image is registered. An object of the one-point registrationis to evaluate what is different from a registration state. For example,the one-point registration is used in a mode for registering thebackground image to cause the user to grasp a background state and, whensome work is conveyed, reacting to the conveyance of the work.

(Procedure of the Two-Point Registration for Registering theNon-Defective Product Image and the Defective Product Image)

As specific teaching, a procedure of the two-point registration isexplained with reference to a flowchart of FIG. 6 viewed from the imageprocessing sensor side and FIGS. 7 to 11. As an example of the two-pointregistration, two images of a non-defective product image and adefective product image are registered.

First, in step S600, the image processing sensor starts processing. Instep S601, the image processing sensor determines presence or absence ofswitching to a two-point registration mode. The image processing sensordetermines presence or absence of short-press of the SET key 42, whichis a form of the operation unit 51. Specifically, the image processingsensor measures, from the operation screen of the display unit 43operating in the operation mode shown in FIG. 7, a time in which the SETkey 42 is depressed. When the time is equal to or shorter than apredetermined number of seconds (e.g., three seconds), the imageprocessing sensor determines that the short-pressed is performed. Whenthe short-press is detected, the image processing sensor proceeds tostep S602. When the short-press is not detected, the image processingsensor stops the processing of the two-point registration mode. In anexample shown in FIG. 6, the image processing sensor returns to stepS600. Note that, instead of returning to step S600, the image processingsensor may shift the two-point registration mode to a three-pointregistration mode explained below.

Subsequently, in step S602, the image processing sensor performsregistration of the first image on the first registration screen. Theimage processing sensor causes the display unit 43 to display a capturedimage. Specifically, first, the image processing sensor reads out, fromthe registration-identification-instruction-information storing unit,the first registration induction information, which is instructioninformation for registering a non-defective product image, and causesthe display unit 43 to display the first registration inductioninformation. A display example of the first registration screen on thedisplay unit 43 is shown in FIG. 8. In the display unit 43, the imagedisplay region PD (the left side in FIG. 8) and the explanation displayregion ED (the right side) are provided. The display unit 43 displays alive image in the image display region PD and displays registrationinduction information in the explanation display region ED. Theregistration induction information indicates, to the user, guidance forinstructing the user to register a non-defective product image as thefirst image. In this example, the image processing sensor causes thedisplay unit 43 to display “SET PRESENCE” to instruct registration of animage in a “detected work presence (non-defective product)” state. Inthis way, the display control unit 58 f causes the display unit 43 todisplay the first registration induction information to urge the user toplace non-defective work, which should be registered as a non-defectiveproduct image, in a screen visual field and cause the imaging unit 21 toimage the non-defective work. According to such display, the user canunderstand that a motion for placing the non-defective work is necessaryat this timing. The user is guided to place the non-defective workaccording to the induction.

Subsequently, the display control unit 58 f causes the display unit 43to display a current image captured by the imaging unit 21 on the firstregistration screen. As explained above, the image display region PD isin the live image display state for updating display content on areal-time basis. When the user places the non-defective work in thescreen visual field according to the first registration inductioninformation, the user can check the non-defective work on the displayunit 43 on a real-time basis as shown in FIG. 9 according to a liveimage display function. A live image displayed on the display unit 43 atthis stage is a candidate of a non-defective product image. In this way,the display form of candidate images of the first image is the liveimage display. Therefore, when the user changes a position where thenon-defective work is placed and a rotation angle, display content ofthe display unit 43 is immediately reflected. Therefore, there is anadvantage that the user can easily adjust an image registered as anon-defective product image obtained by imaging the non-defective workto a desired state. That is, the user visually checks, on the displayunit 43, whether size, a visual field, and the like are appropriate inregistering the image as the non-defective product image. When there isno problem, the user performs registration of the image currentlydisplayed on the display unit 43.

(Display Magnification Adjusting Function)

It is also possible to adjust display magnification of the live imagedisplayed in the image display region PD and enlarge or reduce anddisplay the image. According to such an enlarging and reducing function,it is possible to effectively utilize the display unit 43 having alimited display area. The enlargement and the reduction may bemagnification adjustment of an optical lens provided in the imaging unit21 besides digital zoom of a captured optical image.

In the example shown in FIG. 9, in order to indicate that such enlargingand reducing operation is possible, an icon showing characters “ZOOM”and an increase/decrease icon 61 showing up/down arrows are displayed inthe explanation display region ED as enlargement and reductionpossibility display information. According to such visual display, theuser is informed that enlargement and the like of an image are possibleon the screen. Specifically, the user can perform image enlarging orreducing operation by operating the up/down keys 44, which are a form ofthe increase/decrease adjusting unit 51 h provided on the displaysurface 40 a shown in FIG. 3A and the like. For example, as shown inFIG. 10, when the ⇑ key 44 a of the up/down keys 44 is depressed, theimage is enlarged and displayed. When the ⇓ key 44 b is depressed, theimage is reduced and displayed. Note that, by matching a mark of theincrease/decrease icon 61 and a mark attached to the up/down keys 44,which are the increase/decrease adjusting unit 51 h, it is possible tocause the user to visually grasp a correspondence relation between themarks and urge smoother operation. In the examples shown in FIG. 3A andFIG. 9, A and V are displayed on the up/down keys 44 and Δ and ∇ aredisplayed on the increase/decrease icon 61. By matching these kinds ofdisplay, the correspondence relation is visually shown.

The display unit can be formed as a touch panel. The increase/decreaseicon 61 provided side by side with the “ZOOM” icon can be caused tofunction as the increase/decrease adjusting unit 51 h. For example, theimage may be enlarged when the Δ icon is touched and may be reduced whenthe ∇ icon is touched.

In this way, the “ZOOM” icon, which is an example of theincrease/decrease icon 61, is displayed on a screen on which the imageenlargement and reduction display is possible. The “ZOOM” icon is notdisplayed on a screen on which the image enlarging and reducing functionis disabled. Consequently, it is possible to inform the user that theimage enlarging and reducing function can be used.

Note that, in the example shown in FIG. 9, the enlargement and reductionpossibility display information is displayed in the explanation displayregion ED. However, for example, the display of the enlargement andreduction possibility display information is not limited to thisconfiguration. For example, the enlargement and reduction possibilitydisplay information maybe displayed in the image display region or maybe displayed across the image display region and the explanation displayregion.

In this way, in a state in which the non-defective product image, thevisual field and the magnification of which are appropriately adjustedaccording to necessity, is displayed in the image display region PD, theuser depresses the SET key 42, which is a form of the operation unit 51,to register, as a non-defective product image, a live image displayed inthe image display region PD. A specific flow of this processing isexplained referring back to the flowchart of FIG. 6.

First, in step S603, the image processing sensor detects presence orabsence of an operation instruction from the operation unit 51. Theimage processing sensor determines whether the user operates the SET key42, which is a form of the operation unit 51. When the operationinstruction is absent, that is, the user does not depress the SET key42, the image processing sensor proceeds to step S604 and detectspresence or absence of a magnification change instruction. The imageprocessing sensor detects presence or absence of operation of theincrease/decrease adjusting unit 51 h. In the example of the displaysurface 40 a shown in FIG. 3A and the like, the up/down keys 44, whichare increase/decrease buttons, correspond to the increase/decreaseadjusting unit 51 h.

When the operation of the increase/decrease adjusting unit 51 h isdetected in step S604, the image processing sensor proceeds to step S605and changes display magnification in the display unit 43. In the exampleshown in FIG. 3A and the like, the display magnification is increasedand an image is enlarged and displayed (zoom-in or tele) when the ⇑ key44 a of the up/down keys 44 is depressed. On the other hand, the displaymagnification is reduced and the imaging region is widened (zoom-out orwide) when the ⇓ key 44 b is depressed. Thereafter, the image processingsensor proceeds to step S606. Alternatively, the image processing sensormay return to step S602 and repeat the display.

On the other hand, when the operation of the increase/decrease adjustingunit 51 h is not detected in step S604, the image processing sensorproceeds to step S606 and determines presence or absence of acancellation instruction. The cancellation instruction is performed fromthe cancellation instructing unit. In the example of the display surface40 a shown in FIG. 3A and the like, the BACK key 45 corresponds to thecancellation instructing unit. The BACK key 45 is a key that the useroperates when stopping the image registration processing and the like.When the cancellation instruction is detected, the image processingsensor stops the processing (e.g., returns to step S600 or stops thetwo-point registration and returns to the operation screen shown in FIG.7).

When the operation instruction is received in step S603, that is, whenthe user depresses the SET key 42, the image processing sensor proceedsto step S607 and registers, as a non-defective product image, a liveimage currently being displayed in the image display region PD.

Further, in step S608, the image processing sensor performs registrationof the second image from the second registration screen. Therefore, theimage processing sensor needs to capture an image anew and cause thedisplay unit to display the image. The image processing sensor readsout, from the registration-identification-instruction-informationstoring unit, the second registration induction information, which isinstruction information or induction information for registering adefective product image, causes the display unit 43 to display thesecond registration induction information, and configures the secondregistration screen. Specifically, as shown in FIG. 11, the displaycontrol unit 58 f causes the display unit 43 to display the secondregistration induction information and urges the user to place, in thescreen visual field, defective work that should be registered as adefective product image. Consequently, the user can understand that workfor placing the defective work is necessary at this timing. The user isguided to work that the user should perform. In other words, with visualinduction through the display unit 43, it is possible to avoid a riskthat the user mistakes timing for placing non-defective work and timingfor placing defective work.

When the user places the defective work according to the secondregistration induction information displayed on the second registrationscreen of the display unit 43 in this way, an image captured anew by theimaging unit 21 is displayed on the display unit 43. Specifically, thedisplay control unit 58 f causes the display unit 43 to display, as alive image, a current image serving as a candidate of a defectiveproduct image. In this state, as shown in FIG. 11, the user can check alive image serving as a candidate of a defective product image obtainedby imaging the defective work on the display unit 43. Specifically,before registering the live image as the defective product image, theuser can visually check whether there is no problem in size, a visualfield, and the like and can register the defective product image afterdetermining that the defective product image can be registered. In anexample shown in FIG. 11, “SET NG” is displayed in the explanationdisplay region ED to instruct to register a “detected work is present(defective product)” state as the second registration inductioninformation. On the other hand, an image serving as a candidate of thedefective product image is displayed in the image display region PD asalive image.

Subsequently, in step S609, the image processing sensor detects whetheran operation instruction is received from the operation unit 51. Whenthe operation instruction is not received, that is, the user does notdepress the SET key 42, the image processing sensor proceeds to stepS610 and determines presence or absence of a cancellation instruction.When depression of the BACK key 45 is detected, the image processingsensor returns to step S602. When operation of the BACK key 45 is notdetected, the image processing sensor returns to step S608 and repeatsthe processing.

Note that, in the registration of the defective product image, thedisplay magnification changing function is not carried out. This isbecause, in image processing such as acquisition of a differenceexplained below, it is necessary to match magnifications of thenon-defective product image and the defective product image. Therefore,by maintaining, during the registration of the defective product image,display magnification set during the registration of the non-defectiveproduct image, it is possible to directly register images having thesame magnification and smoothly perform subsequently image work. Scalesof the non-defective product image and the defective product image areoften generally the same degree. Therefore, it is considered that thedefective product image can also be often appropriately captured even atmagnification set in the non-defective product image.

However, for example, when the defective work is larger than thenon-defective work, the user may desire to change the magnification. Inthis case, change of the display magnification may be added with respectto the candidate of the defective product image as in the candidate ofthe non-defective product image. For example, the image processingsensor causes the display unit 43 shown in FIG. 11 to display theenlargement and reduction possible display information like the “ZOOM”icon. Note that, in this case, it is desirable to register thenon-defective product image again in order to match displaymagnification of a registered non-defective product image with displaymagnification of the defective product image. However, the non-defectiveproduct image and the defective product image may be enlarged or reducedto match the magnification of the non-defective product image and themagnification of the defective product image using digital zoom or thelike. In this case, it is possible to save labor and time for capturingthe non-defective product image again.

On the other hand, when the operation instruction is received in stepS609, that is, when the user depresses the SET key 42, the imageprocessing sensor proceeds to step S611 and registers, as the defectiveproduct image, a live image being currently displayed in the imagedisplay region PD.

Further, the image processing sensor proceeds to step S612 and saves theregistered non-defective product image and the registered defectiveproduct image in the image/setting storing unit 54. The image processingsensor proceeds to step S613, calculates a matching degree thresholdfrom the non-defective product image and the defective product image,and further sets the calculated matching degree threshold. In this way,the image processing sensor can perform the two-point registration,automatically calculate an appropriate matching degree threshold fromthe non-defective product image and the defective product image, and setthe matching degree threshold. The image processing sensor may cause thedisplay unit 43 to display the set matching degree threshold. The imageprocessing sensor may enable the user to check the matching degreethreshold by switching the registration screen of the setting mode tothe operation screen during the operation. For example, by returning tothe operation mode after the end of the setting mode of the two-pointregistration, on the operation screen shown in FIG. 7, the imageprocessing sensor may cause the display unit 43 to display the setmatching degree threshold and enable the user to check a numericalvalue. The image processing sensor may be configured to cause thedisplay unit 43 to flash and display a matching degree threshold setanew or updated and indicate that the matching degree threshold is setor updated.

As explained above, the registration of the non-defective product image(step S607) and the switching to the screen for registration of thedefective product image (step S608) are simultaneously performed byoperating the operation unit 51 once. The registration of the defectiveproduct image (step S611) and the registration processing to thecalculation of the matching degree threshold (step S612 and subsequentsteps) are also simultaneously performed by operating the operation unit51 once. Consequently, the user can advance the setting work of thetwo-point registration simply by pressing the SET key 42. In otherwords, it is possible to set a matching degree threshold suitable forthe pass/fail determination by performing the work for placing work anddepression of the SET key 42 according to the induction displayed on thescreen of the display unit 43 without requiring complicated operation.

Note that power saving is achieved by collectively performing theseoperations by operating the operation unit 51 once. However, on theother hand, the respective operations can be individually instructed.For example, it is also possible to operate the operation unit toperform the registration of the non-defective product image and furtheroperate the operation unit to perform the switching to the screen forregistration of the defective product image.

As explained above, it is possible to select feature values in which adifference between the non-defective product image and the defectiveproduct image conspicuously appears. That is, since a work region of thenon-defective product and the defective product are extracted using thedifference, it is possible to perform adjustment for maximizing afeature difference in the region. It is possible to obtain an advantagethat the registration work can be easily performed. That is, the useronly has to push the SET key 42 while viewing an image. It is possibleto eliminate the need for a tool frame and parameter setting of theimage processing sensor in the past.

(Procedure of the Two-Point Registration for Registering theNon-Defective Product Image and the Background Image)

In the example explained above, the two-point registration forregistering the two images of the non-defective product image and thedefective product image is explained. However, the two-pointregistration is not limited to the combination of the images and can bea combination of other images. For example, the two-point registrationof the two images of the non-defective product image and the backgroundimage without work may be performed. Such an example is explained withreference to a flowchart of FIG. 12.

First, in step S1200, the image processing sensor starts processing. Instep S1201, the image processing sensor determines presence or absenceof switching to the two-point registration mode. The image processingsensor determines presence or absence of short-press of the SET key 42.When the short-press is detected, the image processing sensor proceedsto step S1202. When the short-press is not detected, the imageprocessing sensor stops the processing of the two-point registrationmode.

Subsequently, in step S1202, the image processing sensor performsregistration of the first image on the first registration screen. Theimage processing sensor causes the display unit 43 to display a capturedimage. Specifically, first, the image processing sensor reads out, fromthe registration-identification-instruction-information storing unit,the first registration induction information, which is instructioninformation for registering a non-defective product image, and causesthe display unit 43 to display the first registration inductioninformation (FIG. 8). The display control unit 58 f causes the displayunit 43 to display the first registration induction information to urgethe user to place non-defective work, which should be registered as anon-defective product image, in the screen visual field and cause theimaging unit 21 to image the non-defective work. According to suchdisplay, the user can understand that a motion for placing thenon-defective work is necessary at this timing. The user is guided toplace the non-defective work according to the induction.

Subsequently, in step S1203, the display control unit 58 f causes thedisplay unit 43 to display a current image captured by the imaging unit21. The display unit 43 is in the live image display state for updatingdisplay content on a real-time basis. In this state, the user can checkthe live image serving as a candidate of a non-defective product image,which is obtained by imaging the non-defective work, on the display unit43 as shown in FIG. 9. Specifically, the user checks whether there is aproblem in size, a visual field, and the like in registering thenon-defective work as the non-defective product image. When there is noproblem, the user operates the operation unit 51 (the SET key 42) .

Subsequently, in step S1204, the image processing sensor detects whetheran operation instruction from the operation unit 51 is received. Whenthe operation instruction is not received, that is, when the user doesnot operate the operation unit 51, the image processing sensor proceedsto step S1205 and determines whether a “return” instruction is received.For example, in the example of the operation unit 51 shown in FIG. 3Aand the like, the BACK key 45 corresponds to the return instruction. TheBACK key 45 is a key that the user operates to stop the registration ofthe non-defective product image. When the operation of the BACK key 45is detected, the image processing sensor returns to step S1200. When theoperation of the BACK key 45 is not detected, the image processingsensor returns to step S1203 and repeats the processing.

On the other hand, when the operation instruction is received in stepS1204, that is, when the user operates the operation unit 51, the imageprocessing sensor proceeds to step S1206 and registers, as anon-defective product image, a live image being currently displayed inthe image display region PD. The procedure explained above is the sameas the procedure of the two-point registration for registering thenon-defective product image and the defective product image shown inFIG. 6 explained above.

Further, in step S1207, the image processing sensor performsregistration of the second image on the second registration screen.Specifically, the image processing sensor reads out, from theregistration-identification-instruction-information storing unit, thesecond registration induction information, which is instructioninformation for registering a background image, and causes the displayunit 43 to display the second registration induction information. Asshown in FIG. 13, the display control unit 58 f causes the display unit43 to display the second registration induction information and urgesthe user to remove non-defective work, which should be registered as abackground image, from an imaging position. The user can understand thata motion for removing work is necessary according to the displayedsecond registration induction information. The user is induced toperform a motion necessary at this stage. In other words, with visualinduction through the display unit 43, it is possible to avoid a riskthat the user mistakes timing for placing non-defective work and timingfor removing defective work.

Subsequently, in step S1208, the image processing sensor causes thedisplay unit 43 to display a current image (a candidate of a backgroundimage) captured by the imaging unit 21. The display unit 43 may displaythe background image as a still image besides displaying the backgroundimage as a live image (FIG. 13). That is, unlike the work, adjustment ofthe visual field and the size of the background image is unnecessary.Therefore, it is sufficient to confirm that the work is absent.Therefore, the object can be achieved even if the background image isdisplayed as the live image. There is an advantage that it is possibleto simplify the processing by displaying the still image. When there isno problem in registering the non-defective work as the backgroundimage, the user operates the operation unit 51 (the SET key 42). Notethat the display of the background image may be omitted.

Subsequently, in step S1209, the image processing sensor detects whetheran operation instruction is received from the operation unit 51. Whenthe operation instruction is not received, that is, when the user doesnot operate the operation unit 51, the image processing sensor proceedsto step S1210 and determines whether a “return” instruction is received.When the operation of the BACK key 45 is detected, the image processingsensor returns to step S1201. When the operation of the BACK key 45 isnot detected, the image processing sensor returns to step S1208 andrepeats the processing.

On the other hand, when the operation instruction is received in stepS1209, that is, when the user operates the operation unit 51, the imageprocessing sensor proceeds to step S1211 and registers, as a backgroundimage, an image currently being displayed in the image display regionPD.

Further, in step S1212, the image processing sensor saves the registeredtwo images in the image/setting storing unit 54. In step S1213, theimage processing sensor calculates a matching degree threshold from thenon-defective product image and the background image and sets thematching degree threshold. In this way, it is possible to perform thetwo-point registration, automatically calculate an appropriate matchingdegree threshold from the non-defective product image and the backgroundimage, and set the matching degree threshold.

As explained above, it is possible to perform distinction processingwith the influence of a background eliminated. That is, by registeringthe background image, it is possible to perform an evaluation that isless easily affected by background elements.

Note that, in the example explained above, the procedure for registeringthe non-defective product image as the first registration screen andsubsequently registering the background image as the second registrationscreen is explained. In this way, the order of registering images duringteaching is specified in advance. The registration induction informationis used such that the user does not mistake images that should beregistered and the order of the registration. However, the order ofregistering the images is not limited to the example explained above. Itgoes without saying that it is possible to specify the order as anyorder for, for example, registering the background image first andsubsequently registering the non-defective product image.

(Three-Point Registration)

The two-point registration for registering the two points of thenon-defective product image and the other image is explained above.However, in the present invention, images to be registered are notlimited to the two images. Three or more images can also be registered.Most of image processing sensors in the past register only one image andenable a plurality of image processing tools to be set with respect tothe image. In other words, an image processing sensor that registers aplurality of images is hardly present. When work for setting a pluralityof image processing tools with respect to one image is assumed as workon the user side, the user needs to perform work for, for example,selecting, out of a plurality of image processing tools prepared inadvance, a tool necessary for detection of image processing desired bythe user, setting a window as a region to which the tool is applied,selecting parameters of the image processing, and setting or finelyadjusting the parameters. It is difficult for a user to appropriatelyperform such work unless the user understands effects and uses ofprepared image processing tools and has a certain degree of knowledge.Further, the work itself is also troublesome.

From the image processing sensor side, when one non-defective productimage is registered, since the non-defective product image is registeredas a whole, the non-defective product image is registered as an imageincluding a background. Therefore, the image processing of the imageincluding the background image is performed and the pass/faildetermination is performed. A background portion is present not only inthe non-defective product image but also in the defective product image.Therefore, if the background portion is large, a difference between thedefective product image and the non-defective product image decreases.It is difficult to detect a defective product. On the other hand, when alight amount of the sunlight changes between the daytime and the nightand a light amount and a tint of illumination light change, it is likelythat even a non-defective product is distinguished as a defectiveproduct according to a difference of the illumination light. In thisway, the image processing sensor in the past cannot determine a boundarybetween a region of target work and a background. Therefore, the imageprocessing is performed on a portion including the portion of thebackground, which is originally unnecessary, in the pass/faildetermination and fail/pass determination. As a result, a differencebetween the non-defective product and the defective product depends onthe background and the illumination light as well. The image processingcannot be appropriately performed on the basis of the difference betweenthe non-defective product and the defective product desired to bedetected.

On the other hand, in this embodiment, the three images of thenon-defective product image, the defective product image, and thebackground image are registered. Therefore, it is possible to extractnon-defective work and defective (NG) work excluding the background canbe extracted. It is possible to improve the accuracy of the pass/faildetermination. Specifically, by registering not only the non-defectiveproduct image but also the background image, it is possible to extractan unnecessary portion such as the background and exclude theunnecessary portion from the distinction target. Further, in theregistration of the images, it is possible to calculate and set anappropriate matching degree threshold simply be sequentially registeringthe three images. It is possible to eliminate the need for thecomplicated work for, for example, setting a window and setting imageprocessing parameter as in the past. Substantial power saving of thesetting work itself is realized.

More specifically, in this embodiment, in the three-point registration,the three images of the non-defective product image, the defectiveproduct image, and the background image are registered. A differencebetween the non-defective product image and the background image and adifference between the defective product image and the background imageare extracted according to the three images. Consequently, it ispossible to extract non-defective work and defective work excluding thebackground.

In FIG. 14A, an example is shown in which a simple differential imagefrom which only the non-defective work is extracted is generatedexcluding a background image BGI from a non-defective product image GDI.In FIG. 14B, an example is shown in which a simple differential imagefrom which only defective work is extracted is generated excluding thebackground image BGI from a defective product image NGI. In such adifferential image, a difference is obtained by subtractingcorresponding pixels of the two images from each other.

However, “differential” in this specification is not limited to simpledifferential processing for subtracting the corresponding pixels fromeach other. For example, “differential” used in a meaning includingexcluding an element common to a background to specify a work region.

(Procedure of the Three-Point Registration)

A procedure for performing the three-point registration for registeringthe three images of the non-defective product image, the defectiveproduct image, and the background image in the setting mode is explainedbelow with reference to a flowchart of FIGS. 15A and 15B and FIGS. 16 to18.

First, in step S1500, the image processing sensor starts processing. Instep S1501, the image processing sensor determines presence or absenceof switching to the three-point registration mode. The image processingsensor determines presence or absence of long-press of the SET key 42.Specifically, the image processing sensor measures, from the operationscreen of the display unit 43 shown in FIG. 7, a time in which the SETkey 42 is depressed. When the time is equal to or longer than apredetermined number of seconds (e.g., three seconds), the imageprocessing sensor determines that the long-press is performed. When thelong-press is detected, the image processing sensor proceeds to stepS1502. When the long-press is not detected, the image processing sensorstops the processing of the three-point registration mode. In an exampleshown in FIGS. 15A and 15B, the image processing sensor returns to stepS1500. Note that the image processing sensor may shift the three-pointregistration mode to the two-point registration mode in the case of theshort-press.

Subsequently, in step S1502, the image processing sensor performsregistration of the first image on the first registration screen. Theimage processing sensor causes the display unit 43 to display a capturedimage. Specifically, first, the image processing sensor reads out, fromthe registration-identification-instruction-information storing unit,the first registration induction information, which is instructioninformation for registering a non-defective product image, and causesthe display unit 43 to display the first registration inductioninformation. The display control unit 58 f causes the display unit 43 todisplay the first registration induction information to urge the user toplace non-defective work, which should be registered as a non-defectiveproduct image, in the screen visual field and cause the imaging unit 21to image the non-defective work. According to such display, the user canunderstand that a motion for placing the non-defective work is necessaryat this timing. The user is guided to place the non-defective workaccording to the induction.

Further, the image processing sensor causes the display unit 43 todisplay a current image captured by the imaging unit 21. The displayunit 43 is in the live image display state for updating display contenton a real-time basis. In this state, as shown in FIG. 16, the user cancheck, on the display unit 43, a live image serving as a candidate ofthe non-defective product image GDI obtained by imaging thenon-defective work. Specifically, in registering the live image as thenon-defective product image GDI, the user checks whether there is noproblem in size, a visual field, and the like. When there is no problem,the user operates the operation unit 51 (the SET key 42).

Note that, in an example shown in FIG. 16, registration orderinformation 63 indicating the order of the images that should beregistered is displayed on the explanation display region ED (detailsare explained below). A “ZOOM” icon is also provided as enlargement andreduction possibility display information. The registration orderinformation 63 is arranged in an upper part of the explanation displayregion ED and the enlargement and reduction possibility displayinformation is arranged in a lower part of the explanation displayregion ED. However, the registration order information 63 and theenlargement and reduction possibility display information are notlimited to this arrangement example. Further, in the image displayregion PD, guide lines GDL for absorbing differences of work aredisplayed (details are explained below).

Subsequently, in step S1503, the image processing sensor detects whetheran operation instruction from the operation unit 51 is received. Whenthe operation instruction is not received, that is, when the user doesnot depress the SET key 42, the image processing sensor proceeds to stepS1504 and detects presence or absence of a magnification changeinstruction. The image processing sensor detects presence of absence ofoperation of the increase/decrease adjusting unit 51 h. In the exampleof the display surface 40 a shown in FIG. 3A and the like, the imageprocessing sensor detects presence or absence of depression of theup/down keys 44, which are the increase/decrease buttons. When theoperation of the increase/decrease adjusting unit 51 h is detected instep S1504, the image processing sensor proceeds to step S1505 andchanges display magnification. Thereafter, the image processing sensorproceeds to step S1506. Alternatively, the image processing sensor mayreturn to step S1502 and repeat the display. On the other hand, when theoperation of the increase/decrease adjusting unit 51 h is not detectedin step S1504, the image processing sensor proceeds to step S1506 anddetermines presence or absence of a cancellation instruction. The imageprocessing sensor determines whether a “return” instruction is received.When the operation of the BACK key 45 is detected, the image processingsensor returns to step S1500. When the operation of the BACK key 45 isnot detected, the image processing sensor returns to step S1502 andrepeats the processing. Alternatively, the image processing sensor maystop the three-point registration and return to the operation screenshown in FIG. 7.

On the other hand, when the operation instruction is received in stepS1503, that is, when the user operates the operation unit 51, the imageprocessing sensor proceeds to step S1507 and registers, as thenon-defective product image GDI, a live image being currently displayedin the image display region PD.

Further, in step S1508, the image processing sensor performsregistration of the second image on the second registration screen.Specifically, the image processing sensor reads out, from theregistration-identification-instruction-information storing unit, thesecond registration induction information, which is instructioninformation for registering a defective product image, and causes thedisplay unit 43 to display the second registration inductioninformation. The display control unit 58 f causes the display unit 43 todisplay the second registration induction information and urges the userto place defective work, which should be registered as a defectiveproduct image, in the screen visual field.

Further, the image processing sensor causes the display unit 43 todisplay a current image (a candidate of a defective product image)captured by the imaging unit 21. An example of such a secondregistration screen is shown in FIG. 17. The image processing sensorcauses the display unit 43 to display a candidate of the defectiveproduct image NGI in the image display region PD as a live image. Inorder to register the current image as the defective product image NGI,the user performs adjustment of an imaging position, a posture, andmagnification according to necessity. When determining that the currentimage can be registered on the live image, the user operates theoperation unit 51 (the SET key 42).

Subsequently, in step S1509, the image processing sensor detects whetheran operation instruction from the operation unit 51 is received. Whenthe operation instruction is not received, that is, when the user doesnot operate the operation unit 51, the image processing sensor proceedsto step S1510 and determines whether a cancellation instruction isreceived. When a “return” instruction, for example, the depression ofthe BACK key 45 is detected, the image processing sensor performspredetermined operation for, for example, stopping the processing andreturning to step S1500. When the depression of the BACK key 45 is notdetected, the image processing sensor returns to step S1508 and repeatsthe processing.

On the other hand, when the operation instruction is received in stepS1509, that is, when the user operates the operation unit 51, the imageprocessing sensor proceeds to step S1511 and registers, as the defectiveproduct image NGI, a liver image currently being displayed in the imagedisplay region PD.

Further, in step S1512, the image processing sensor performsregistration of the third image on the third registration screen.Specifically, the image processing sensor reads out third registrationinduction information, which is instruction information for registeringa background image, and causes the display unit 43 to display the thirdregistration induction information. The display control unit 58 f causesthe display unit 43 to display the second registration inductioninformation and urges the user to remove the defective work from theimaging position in order to capture a background image. According tothe displayed third registration induction information, the user isinstructed to remove the work and induced to perform necessary work,that is, capture a background image without the work. Consequently, thecaptured background image BGI is displayed in the image display regionPD. An example of such a third registration screen is shown in FIG. 18.Note that the background image can be displayed as a still image asexplained above besides being displayed as the live image. That is,unlike the work, adjustment of the visual field and the size of thebackground image is unnecessary. Therefore, it is sufficient to confirmthat the work is absent. Therefore, the object can be achieved even ifthe background image is displayed as the live image. There is anadvantage that it is possible to simplify the processing by displayingthe still image. Alternatively, the display of the background image maybe omitted. When there is no problem in registering the non-defectivework as the background image, the user operates the operation unit 51(the SET key 42).

Further, in step S1513, the image processing sensor detects whether anoperation instruction from the operation unit 51 is received. When theoperation instruction is not received, for example, when the user doesnot depress the SET key 42, the image processing sensor proceeds to stepS1514 and determines whether a cancellation instruction is received.When, for example, the operation of the BACK key 45 is detected as a“return” instruction, the image processing sensor performs predeterminedprocessing for, for example, returning to step S1512. When the operationof the BACK key 45 is not detected, the image processing sensor returnsto step S1512 and repeats the processing.

On the other hand, when the operation instruction is received in stepS1513, for example, when the user depresses the SET key 42, the imageprocessing sensor proceeds to step S1515 and registers, as thebackground image BGI, an image currently being displayed in the imagedisplay region PD.

Further, in step S1516, the image processing sensor saves the registeredthree images in the image/setting storing unit 54. In step S1517, theimage processing sensor calculates a matching degree threshold from thenon-defective product image GDI, the defective product image NGI, andthe background image BGI and sets the matching degree threshold. In thisway, the image processing sensor can perform the three-pointregistration, automatically calculate an appropriate matching degreethreshold from the non-defective product image GDI, the defectiveproduct image NGI, and the background image BGI, and set the matchingdegree threshold.

In the example of the three-point registration, the image processingsensor causes the enlarging and reducing function to function only whenthe non-defective product image GDI is registered on the firstregistration screen and does not cause the enlarging and reducingfunction to work on the second registration screen and the thirdregistration screen. That is, the image processing sensor registers thesecond image and the third image while keeping the magnification set onthe first registration screen fixed. Complication and disorder ofsetting work of the user are avoided by control for automaticallyturning on/off such an enlarging and reducing function to achievesimplification of operation. However, the enlarging and reducingfunction may be turned on the second registration screen and the thirdregistration screen.

In the example of the three-point registration explained above, theprocedure for registering the non-defective product image GDI as thefirst registration screen first, subsequently registering the defectiveproduct image NGI as the second registration screen, and registering thebackground image BGI as the third registration screen is explained. Theorder of registering the images is not limited to the order explainedabove. It goes without saying that it is possible to specify any orderfor, for example, registering the background image as the secondregistration screen first and subsequently registering the defectiveproduct image.

(Procedure of the One-Point Registration for Registering theNon-Defective Product Image or the Background Image)

Further, a procedure of the one-point registration for registering anon-defective product image or a background image is explained withreference to FIG. 19. First, in step S1901, the image processing sensoracquires a background image. For example, the image processing sensoracquires the background image BGI shown in FIG. 20 and saves thebackground image BGI in the image storing unit 54 i. Note that thebackground image may be reduce in resolution on the basis of a responsetime set in advance as explained below.

Subsequently, in step S1902, the image processing sensor sets the entirescreen as an evaluation region. For example, an evaluation region EVD isautomatically set with respect to the background image BGI shown in FIG.20 as indicated by a frame in FIG. 21.

Further, in step S1903, the image processing sensor extracts featurevalues. Specifically, first, in step S1903-1, the image processingsensor extracts feature values of the background image BGI in theevaluation region EVD. For example, feature values such as the number ofedges of 0 and a luminance average of 70 are obtained with respect tothe background image BGI shown in FIG. 21.

Subsequently, in step S1903-2, the image processing sensor determinesweighting of an evaluation with respect to the feature values. Forexample, the image processing sensor selects 50% of the number of edgesand 50% of the luminance average is selected as feature values of thepass/fail determination.

Further, in step S1903-3, the image processing sensor sets a matchingdegree threshold. The image processing sensor automatically sets thematching degree threshold with respect to, for example, the number ofedges and the luminance average.

When the setting mode ends in this way, the image processing sensorshifts to the operation mode. In the operation mode, in step S1904, theimage processing sensor performs an evaluation of an input image. Notethat the image processing sensor does not perform processing such asspecifying of work and cutout of work and regards the entire screen asone work and performs distinction processing.

(Desirable Registration State)

In registering an image in the image/setting storing unit 54 in thesetting mode, the image processing sensor performs the registrationunder desirable registration setting conditions. The desirableregistration setting conditions are conditions under which, when thepass/fail determining unit 57 d performs the pass/fail determination inthe operation mode, the pass/fail determining unit 57 d can stablydistinguish a non-defective product and a defective product. In thedetermination, it is important how the non-defective product and thedefective product can be stably distinguished. In the operation mode,the pass/fail determining unit 57 d performs the pass/fail determinationusing, as an evaluation value, a matching degree of an input live imageand a non-defective product image. As a matching degree calculated bythe matching-degree calculating unit 57 c with respect to the input liveimage, an evaluation value of 0% to 100% is calculated. When the inputlive image is a non-defective product image obtained by imaging anon-defective product, a matching degree of the input live image isideally calculated as 100%. However, when the input live image is adefective product image obtained by imaging a defective product, ingeneral, a matching degree is not 0%. This is because, since a part ofthe non-defective product image is different depending on a chip, acrack, and the like, the defective product image often includes aportion coinciding with the non-defective product image.

(Matching Degree Threshold)

A matching degree threshold serving as a reference of the pass/faildetermination is determined on the basis of a matching degree of adefective product and a matching degree of a non-defective product. Forexample, the threshold calculating unit sets, as the matching degreethreshold, an intermediate value between the matching degree of thenon-defective product, which is generally high, and the matching degreeof the defective product, which is generally low. In order to stablydistinguish the non-defective product and the defective product, thatis, stabilize a determination result, it is desirable to separate thematching degree of the non-defective product and the matching degree ofthe defective product as much as possible such that a difference betweenthe matching degrees is large. Therefore, under a condition in whichdispersion of the matching degree with respect to the non-defectiveproduct can be regarded as constant, the matching degree of thenon-defective product and the matching degree of the defective productare separated such that the difference between the matching degrees islarger as the matching degree of the defective product is calculatedlower. Stable pass/fail determination can be expected. Therefore, aregistration state is considered to be good. Accordingly, it isnecessary to calculate brightness and resolution of an image to becaptured and conditions of image processing such that the non-defectiveproduct and the defective product are separated and a stabledetermination result is obtained. Consequently, it is possible toappropriately set the matching degree threshold serving as the referenceof the pass/fail determination.

Note that the matching-degree calculating unit 57 c and the thresholdcalculating unit 56 c are shown as the separate members in the exampleshown in the block diagram of FIG. 5. However, the present invention isnot limited to this configuration. For example, the matching-degreecalculating unit and the threshold calculating unit may be configured bythe same member.

(Method in Which the Threshold Calculating Unit Sets the Matching DegreeThreshold)

The setting of the matching degree threshold serving as the reference ofthe pass/fail determination is performed by the threshold calculatingunit 56 c. The threshold calculating unit 56 c sets the matching degreethreshold between a matching degree of a defective product image and amatching degree of non-defective product image calculated by thematching-degree calculating unit 57 c. The matching degree threshold isdesirably set in the middle of the matching degrees of the non-defectiveproduct image and the defective product image. As an example, an examplein which, when the matching degree of the non-defective product image isset to 100%, the matching degree threshold is set according to thematching degree of the defective product image is shown in a table ofFIG. 22. For example, when the matching degree of the defective productimage is 80%, the matching degree threshold is set to (100%+80%)/2=90%.Similarly, when the matching degree of the defective product image is70%, the matching degree threshold is set to (100%+700)/2=850. When thematching degree of the defective product image is 60%, the matchingdegree threshold is set to (100%+60%)/2=80%. When the matching degree ofthe defective product image is 50%, the matching degree threshold is setto (100%+50%)/2=75%.

In this way, it is considered that, as the matching degree of thedefective product image is lower, the non-defective product image andthe defective product image are further separated and stability of thepass/fail determination is improved. Therefore, in registration of animage in the image/setting storing unit 54, the aim is to achieve animage registration state in which the matching degree of the defectiveproduct image is low in this way. In an example shown in FIG. 22, thelowest matching degree threshold of 50% is desirable because thedifference between the matching degrees of the non-defective productimage and the defective product image is the largest.

(Determination of Feature Values During Registration)

On the other hand, when the pass/fail determination is performed withonly feature values in which a difference in the matching degreethreshold is the lowest, erroneous determination is sometimes performedin a specific case. For example, in feature values A to D in which thematching degrees of the non-defective product image and the defectiveproduct image indicate values shown in Table 1, the feature value D isconsidered to be desirable because a difference between the matchingdegrees of the non-defective product image and the defective productimage is the largest. However, specific noise resistance is sometimesdeteriorated.

TABLE 1 Non-defective Defective product product image image Featurevalue A 100 60 Feature value B 100 90 Feature value C 100 100 Featurevalue D 100 50

Therefore, it is possible to stabilize a non-defective productdetermination result by, rather than performing the pass/faildetermination with one feature value, performing an evaluation of thepass/fail determination taking into account other feature values. Forexample, in the case of Table 1, the pass/fail determination is notperformed with only the feature value D. The other feature values A andB with which the non-defective product and the defective product can bedistinguished are also evaluated.

(Weighting Setting Unit 56 e)

The image processing sensor can also include a weighting setting unit 56e for setting, in the setting mode, according to a matching degree ofeach of a plurality of different image processing algorithms, for eachof the image processing algorithms, weighting used in calculating thematching degree threshold with the threshold calculating unit 56 c.

In order to perform an evaluation in which a plurality of feature valuesare combined in this way, for example, weighting is performed on theplurality of feature values. The weighting is set larger for the featurevalues in which the difference between the matching degrees of thenon-defective product and the defective product is larger. Conversely,the weighting is set smaller for the feature values in which thedifference between the matching degrees is smaller. For example, in anexample shown in Table 1, weighting of 40% is performed with respect tothe feature value A, weighting of 10% is performed with respect to thefeature value B, weighting of 0% is performed with respect to thefeature value C, and weighting of 50% is performed with respect to thefeature value D. In this case, the feature value C has the weighting of0%. Even if the feature value C is calculated, the feature value C isnot evaluated. Therefore, processing of the feature value C does nothave to be performed during execution of the evaluation of the pass/faildetermination. In this way, the weighting setting unit 56 e isconfigured to, for example, set large weighting with respect to aprocessing flow with a low image matching degree calculated by thematching-degree calculating unit 57 c and, conversely, set smallweighting with respect to a processing flow with a high image matchingdegree. When the image matching degree is low, separability of thenon-defective product and the defective product is considered to beexcellent. Therefore, the weighting is increased. Conversely, when theimage matching degree is high, the separability of the non-defectiveproduct and the defective product is considered to be inferior.Therefore, it is possible to improve the accuracy of the pass/faildetermination as a whole by adjusting to reduce the weighting.

Note that, in the example shown in FIG. 5, the calculation of thematching degree is performed by the matching-degree calculating unit 57c in both of the setting mode and the operation mode. In the settingmode, after performing, with the setting-image processing unit 56, imageregistration operation, the image processing sensor operates theoperation-image processing unit 57 to calculate matching degrees of thenon-defective product and the defective product with the matching-degreecalculating unit 57 c. The image processing sensor calculates athreshold from a result of the calculation of the matching degrees. Onthe other hand, in the operation mode, the matching-degree calculatingunit 57 c calculates a matching degree with respect to an input image onthe basis of the weighting calculated during the setting. In this case,the matching-degree calculating unit 57 c calculates a weighted additionmatching degree obtained by adding the weighting set by the weightingsetting unit 56 e to the image matching degrees calculated for each of aplurality of different processing flows. For example, a final score of amatching degree in evaluating the feature values A to D shown in Table 1with the weighting explained above can be calculated by (a score of thefeature value A)×(weight of the feature value A)+(a score of the featurevalue B)×(weight of the feature value B)+(a score of the feature valueC)×(weight of the feature value C)+(a score of the feature valueD)×(weight of the feature value D).

Further, in the operation mode, when the image matching degreecalculated by the matching-degree calculating unit 57 c reaches apredetermined prohibition threshold, the execution of the processingflow may be prohibited.

(Guide Lines GDL)

In the example shown in FIG. 16 and the like, the guide lines GDLserving as the indicators for positioning of work are shown in the imagedisplay region PD. The guide lines GDL are displayed in a frame shapesurrounding four corners in an L shape. In this way, it is possible tourge the user to perform positioning to arrange, for example, in work,which is an inspection target object, characteristic portions such asparts where signs of a defective product appear are included in theframes of the guide lines GDL. In other words, an effect of causing theuser to be aware that an important image is arranged near the center isobtained. As a result, an evaluation with weight added to a featuredifference is expected. It is possible to stably perform determinationof a matching degree and obtain a determination result with highreliability. The guide lines GDL are not limited to such a frame shape.It is possible to appropriately adopt other forms such as display forinducing the user to arrange work in the center, for example, formingthe guide lines GDL as cross lines or target shapes passing the centerof the image display region PD. Note that ON/OFF of the display of theguide lines GDL may be capable of being switched.

Note that, in the example shown in FIGS. 9 and 13, the characterinformation is displayed in two rows as the first registration inductioninformation. However, the character information may be displayed in onerow. Such an example is shown in FIGS. 23 and 24. In FIG. 23, “OK SET”is displayed in the explanation display region ED as the firstregistration induction information for registering the non-defectiveproduct image GDI on the first registration screen. In FIG. 24, “BG SET”is displayed in the explanation display region ED as the secondregistration induction information for registering the background imageBGI on the second registration screen.

(Registration Order Information 63)

Further, the registration order information 63 indicating registrationorder may be included as registration induction information. Forexample, “1” is displayed on the first registration screen shown inFIGS. 23 and “2” is displayed on the second registration screen shown inFIG. 24. The user can visually grasp a stage of image registration fromthese displays. In this way, not only character strings but also numberscan be used as the registration induction information. The numbers mayindicate types of display screens other than registration order ofimages. For example, “1” may be displayed on the first registrationscreen, “2” may be displayed on the second registration screen, and “3”may be displayed on the third registration screen.

(Induction Information)

In the example explained above, the display control unit 58 f causes thedisplay unit 43 to display the character information as the inductioninformation. However, the present invention is not limited to guidanceby characters. The user can also be induced to follow a procedure ofregistration in another form such as figures, sound, a combination ofthe figures and the sound, or the like. An example in which a figure iscombined with characters to perform a registration instruction is shownin FIGS. 25 and 26. In FIG. 25, a state in which work is placed in thescreen visual field is indicated by a figure as the first registrationinduction information for instructing registration in a “detected workis present” state. FIG. 25 corresponds to FIGS. 9 and 23 referred toabove. In the figure, the “ZOOM” icon may be displayed as theenlargement and reduction possible display information in theexplanation display region ED in order to indicate that enlargement andreduction display of a live image displayed in a display region ispossible. Such enlargement and reduction possible display information isnot limited to be written horizontally as in the example shown in FIG. 9and can be indicated by vertical writing as shown in FIG. 25.Consequently, it is possible to effectively utilize the display regionhaving a limited area.

In FIG. 26, a state in which the work is removed from the imagingposition is indicated by a figure as the second registration inductioninformation for instructing registration in a “detected work is absent”state. FIG. 26 corresponds to FIG. 13 and the like. By displaying thefigure on the display unit 43 in this way, it is possible visuallyinstruct a motion that should be performed and provide an operationenvironment easily understood by the user unaccustomed to operation. Thefigure is not limited to a still image and can also be displayed as amoving image. For example, by displaying, as a moving image or ananimation, a state in which the work is placed by a hand or a state inwhich the work is removed by the hand, it is possible to more clearlyinstruct the user about operation that should be performed.

(Display Switching)

Further, the display unit 43 may be capable of switching and displayinga plurality of display screens. For example, in the example shown inFIGS. 25 and 26, the image display region PD and the explanation displayregion ED are simultaneously displayed on one screen. However, as shownin FIGS. 27 and 28, the image display region PD and the explanationdisplay region ED can also be switched and displayed. Alternatively, notonly the image display region PD and the explanation display region EDbut also images may be switched and displayed. For example, as shown inFIG. 29, candidate images about to be registered and the non-defectiveproduct image GDI already registered are switched and displayed on thesecond registration screen. Consequently, explanations can be displayedtogether with the images. Therefore, it is easier to grasp what isdisplayed by which image. Further, by switching and displaying theimages, it is also possible to compare both the images. Alternatively,as shown in FIG. 30, in the second registration screen, the candidateimages about to be registered and parallel display explained below (thenon-defective product image GDI and the candidate images) can also beswitched and displayed. In this way, the limited display area of thedisplay unit 43 can be more effectively utilized. In particular, whenthe display area of the display unit 43 is narrow, it is possible toavoid a problem in that displayed images and characters are small andthe display unit 43 having high resolution needs to be prepared. As theswitching of the screens, displays can be automatically alternatelyswitched at a fixed cycle. Alternatively, besides such an automaticalternate display function, the user may operate a switching button orthe like to manually perform the switching of the screens.

(Parallel Display Function)

In the two-point registration and the three-point registration, aplurality of images can also be displayed side by side on one screen.For example, after one image is registered in the setting mode, when theother image is registered, the registered image is displayed as a stillimage and the image being currently registered is displayed as a liveimage. An example of such parallel display is shown in FIG. 31. Thefigure shows the second registration screen of the two-pointregistration. It is assumed that the non-defective product image GDI isregistered as the first image in advance on the first registrationscreen of the two-point registration. In this state, on the secondregistration screen on which the defective product image NGI isregistered as the second image, as shown in FIG. 31, a first imagedisplay region PD for displaying the first image and a second displayimage region PD for displaying the second image are provided in theimage display region PD of the display unit 43. Consequently, the usercan register the defective product image NGI while taking into accountthe registered non-defective product image GDI. Such a secondregistration screen can be used instead of the second registrationscreen shown in FIGS. 11 and 13 and the like. Such a parallel displayfunction can also be applied not only to the second registration screenbut also to the third registration screen.

(Still Image/Live Image Simultaneous Display Function)

Further, in the parallel display, it is also possible to display a partof images as a still image and display the other image as a live image.That is, by displaying, as a live image, an image about to be registeredwhile displaying a registered image as a still image, it is easy toadjust, which checking, on a real-time basis, a state in which theposition of work, illumination, and the like are changed, the state toan optimum state. For example, in the example shown in FIG. 31, thenon-defective product image GDI serving as the first image is displayedas a still image in the first image display region PD on the right side.A live image of the defective product image NGI registered as the secondimage is displayed in the second image display region PD on the leftside. The user can adjust a placing method while viewing thenon-defective product image GDI on the right side such that the posture,the size, and the like of the defective produce coincide with theposture, the size, and the like of the non-defective product image GDI.A light amount of illumination and the like can also be adjusted.Consequently, the non-defective product image GDI and the defectiveproduct image NGI can be registered such that the same portions areeasily matched, in other words, in a state in which differences easilybecome distinct when a difference is extracted. Therefore, it is easy tomore highly accurately calculate a matching degree. This is alsoadvantageous in setting a matching degree threshold for distinguishingthe non-defective product image GDI and the defective product image NGI.The non-defective product image GDI already registered is alsodisplayed. Therefore, the user can check whether the non-defectiveproduct image GDI registered earlier is correctly registered. Forexample, when an unintended cut or the like of a background with respectto the non-defective product image occurs, the user can notice the cutor the like and can determine to perform imaging again. Further, bydisplaying the non-defective product image GDI and the defective productimage NGI side by side on the screen of the display unit 43, it ispossible to compare the non-defective product image GDI and thedefective product image NGI and determine as what kind of a differencean actual object of work is reflected on the screen. By enabling theuser to be aware of a state of the registered image in which way, it ispossible to easily create a satisfactory registration state, leading tostabilization of detection.

An example of a procedure for realizing such a still image/live imagesimultaneously display function is shown in a flowchart of FIG. 32. Theflowchart corresponds to a detailed flow of step S608 in the two-pointregistration shown in FIG. 6. First, in step S3201, the image processingsensor acquires a live image. The image processing sensor captures, withthe imaging unit 21, as the second image, a live image of an opticalimage serving as a candidate of a defective-product image. Subsequently,in step S3202, the image processing sensor updates content of a memorythat retains the live image. Specifically, the image processing sensoroverwrites data of a live image captured last time and stored in thelive image memory with data of the live image acquired anew and savesthe data. Note that the memory may be a dedicated memory for the liveimage or may be a common memory. Subsequently, in step S3203, the imageprocessing sensor reads out the saved live image and the non-defectiveproduct image already registered on the first registration screen. Instep S3204, the image processing sensor transfers the images to thedisplay screen. The image processing sensor causes the display unit 43to display the non-defective product image as a still image and displaythe candidate of the defective product image as a live image on thesecond registration screen. Thereafter, the image processing sensorrepeats these steps and realizes real-time display for updating displaycontent of the display unit 43. In this way, the image processing sensoradjusts a position where defective work is placed, the posture of thedefective work, and the like while, in registering the defective productimage, displaying the defective product image as the live image andtaking into account the non-defective product image of the still imageto make it possible to check an image after the adjustment on thedisplay unit 43 on a real time basis. Consequently, an environment inwhich registration work of a desired image can be easily performed isprovided.

In the example explained above, the non-defective product imageregistered on the first registration screen is displayed as the stillimage on the second registration screen and the defective product imageis displayed as the live image. However, the present invention is notlimited to this configuration. For example, it is also possible todisplay, on the second registration screen, as still image, thenon-defective product image registered on the first registration screenand display the background image as the live image. Conversely, it isalso possible to register the background image and the defective productimage on the first registration screen and display and register thenon-defective production image as the live image while displaying theregistered images as still image on the second registration screen.Further, the still image/live image simultaneous display function can beused not only in the two-point registration but also in the three-pointregistration. That is, it is also possible to display, as the stillimage on the second registration screen, the non-defective product imageregistered on the first registration screen, display the defectiveproduct image as the live image, and display the background image as thelive image while displaying the non-defective product image as the stillimage on the third registration screen as well. Alternatively, it isalso possible to display the background image as the live image whiledisplaying the defective product image as the sill image on the thirdregistration screen.

Alternatively, in the three-point registration, the parallel display andthe still image/live image simultaneously display may be combined withindependent display. For example, when the defective product image isregistered on the second registration screen, the parallel display ofthe non-defective product image of the still image and the defectiveproduct candidate images of the live image is performed. When thenon-defective product image is registered on the first registrationscreen and when the background image is registered on the thirdregistration screen, independent image display is performed. Inparticular, in general, it is often sufficient to capture the backgroundimage as it is. Therefore, simplification of the processing is achievedby eliminating the need for the parallel display.

As such a parallel display screen, for example, a registered image and acurrent live image are displayed side by side. As an example, thedisplay unit 43 shown in FIG. 31 displays the registered non-defectiveproduct image GDI (an OK image) and the current live image (an NG image)serving as a candidate of the defective product image NGI side by side.In this case, the normal registration screen and the parallel displayscreen may be switched and displayed. For example, in the three-pointregistration, the second registration screen shown in FIG. 17 and theparallel display screen shown in FIG. 31 can be switched and displayed.Consequently, in the registration of the defective product image, it ispossible to register the defective product image while comparing thedefective product image with the non-defective product image. Similarly,in the registration of the background image, for example, when the thirdregistration screen shown in FIG. 18 is displayed, the thirdregistration screen and a parallel display screen shown in FIG. 33, onwhich the registered defective product image NGI and an image (a stillimage or a live image) currently being registered serving as a candidateof the back ground image BGI are displayed side by side, maybe switchedand displayed. Alternatively, the parallel display screen may be acombination of the non-defective product image and the background imagerather than the combination of the defective product image and thebackground image. Further, the parallel display screen is not limited tothe configuration in which the two images are displayed in parallel.Three or more images may be displayed on one screen.

Note that, in the example explained above, the image display region PDand the explanation display region ED are divided. However, the imagedisplay region PD and the explanation display region ED may be partiallysuperimposed and displayed or may be caused to overlap. For example, inan example shown in FIG. 34, the image display region PD and theexplanation display region ED are caused to partially overlap to displaycharacter information, which is the first registration inductioninformation. Alternatively, as shown in FIG. 35, the image displayregion PD and the explanation display region ED may be caused tocompletely overlap to display the character information. It is alsopossible to integrate the image display region and the explanationdisplay region without distinguishing the regions and incorporate anddisplay the first registration induction information in display of animage. In this way, it is possible to effectively utilize a limitedregion of the display unit. Therefore, in this embodiment, it is notalways necessary to exclusively provide the image display region and theexplanation display region and clearly mark off a boundary. Thisembodiment includes a form in which character information issuperimposed on an image by, for example, arranging the image displayregion and the explanation display region to partially or entirelyoverlap or integrating the image display region and the explanationdisplay region.

Note that, in these examples, the character string and the icon on thedisplay unit are written in English. However, a language is not limitedto English. It goes without saying that the character string and theicon may be written in Japanese and other languages.

In this way, the user is guided to proceed with the setting work in thesetting mode according to the depression of the SET key 42. Therefore,there is an excellent convenience that even a beginner not understandingthe operation principle and the like of the image processing sensor caneasily use the image processing sensor. In particular, in the imagesensor in the past, the setting registration is complicated and, on theother hand, the registration work is completed by simply performing SETkey operation twice in a state in which work is present and a state inwhich work is absent. Therefore, there is a large difference indifficulty of setting between the photoelectric sensor in the past andthe image sensor. There are many users who can perform setting in thephotoelectric sensor in the past but cannot perform setting of the imagesensor. On the other hand, in the image sensor according to thisembodiment, the user can perform the setting of the image processingsensor in feeling same as feeling of setting the photoelectric sensor.Therefore, it is possible to mitigate a barrier in introducing the imageprocessing sensor.

(Operation Mode)

When the setting of the matching degree threshold with respect to theimage matching degree ends as explained above, it is possible to shiftthe image processing sensor from the setting mode to the operation mode.In the operation mode, the image processing sensor captures an image ofwork actually conveyed on a conveyance line, calculates a matchingdegree with respect to an obtained input image, and compares thematching degree with the matching degree threshold to performdetermination of a non-defective product and a defective product.

(A Selecting Function for a Distinction Target and an OperationPrinciple)

A selecting function for a distinction target and an operation principleare explained with reference to FIGS. 55, 56, and 57. FIG. 55 is animage diagram showing a state in which non-defective work WK anddefective work WK are flowing on a manufacturing line. As shown in FIG.55, a detection region of the image processing sensor 100 has width. Aspot diameter of the image processing sensor 100 is, for example, as alarge size, approximately 6 cm×6 cm and, as a small size, approximately2 mm×2 mm. In view of the fact that a spot diameter of a normalphotoelectric sensor is approximately 1.2 mmφ, the spot diameter of theimage processing sensor 100 is considered to be larger than the spotdiameter of the normal photoelectric sensor.

Therefore, in the detection region imaged by the imaging unit 52, forexample, as shown in FIG. 56A, the work WK change in the order of (A) to(F). At this point, in a normal operation state, that is, when a masterimage is a non-defective product image, as shown in FIG. 56B, which isan image diagram of a time-series change of a first matching degree, thefirst matching degree gradually increases from the periphery of (B),reaches a peak at a point in time of (C), and gradually decreases in(D). A slight increase of the first matching degree in (E) means thatelements coinciding with features of the non-defective product image arepresent in a defective product image. An image diagram showing an outputstate in this case is shown in FIG. 56C. As shown in the figure, anoutput is turned on when the first matching degree exceeds the firstthreshold. That is, the output is turned on only when the non-defectivework WK comes.

A time-series change of the output at the time when setting forinverting an output logic like, for example, a negative output of thephotoelectric sensor or turning on the output when the matching degreeis smaller than a threshold is performed on the time-series change ofthe output shown in FIG. 56C is shown in FIG. 56D. As shown in thefigure, in all the cases, (1) a state in which the work WK is absent inthe detection region (a state of (A)) or a state in which the work WKenters the detection region halfway (states of (B), (D), and (F)) and(2) a state in which the defective work WK comes (a state of (E)) cannotbe separated by outputs.

Therefore, in order to recognize that the defective work WK enters thedetection region, it is necessary to notify the sensor with anothermeans that “the work WK enters the detection region and it is timing toperform determination” (the states of (C) and (E)). That is, if “it istiming to perform determination” and “the determination output is OFF”,it is possible to recognize that the defective product WK comes.

When setting for causing the defective product image to operate as themaster image is selected, a time-series change of the second matchingdegree shown in FIG. 57B and a time-series change of the output shown inFIG. 57C are obtained with respect to, for example, the flow of the workWK that changes in the order of (A) to (F) shown in FIG. 57.

That is, during the defective product output setting, the secondmatching degree gradually increases from the periphery of (D), reaches apeak at a point in time (E), and gradually decreases in (F). In thiscase, as shown in FIG. 57C, when the second matching degree exceeds thethird threshold, the output is turned on. That is, the output is turnedon only when the defective work comes.

When the setting for causing the defective product image to operate asthe master image is selected in this way, it is possible to performcontrol for discharging the defective product using the output as atrigger. The image processing sensor 100 according to this embodimentcan select whether to cause the non-defective product image to operateas the master image or to cause the defective product image to operateas the master image. Therefore, the image processing sensor 100 iscapable of coping with, with one setting change, both of a user whoperforms discharge control and the like when the defective product comes(a user who desires to learn that the defective product comes) and auser who performs counting and the like when the non-defective productcomes (a user who desires to learn that the non-defective productcomes).

For example, when a desired determination result is not obtainedaccording to the determination result in the operation mode or when theuser desires to adjusts the setting to setting further improved inaccuracy, it is possible to shift to the setting mode again and performupdate of the setting. Alternatively, during the operation mode, it isalso possible to temporarily change registration setting conditions. Forexample, the matching degree threshold is finely adjusted according to aresult of the pass/fail determination (details are explained below).

Such switching of the operation mode and the setting mode is performedfrom the operation/setting-mode switching unit 51 d. As an example ofthe operation/setting-mode switching unit 51 d, the SET key 42 is usedin the image processing sensor shown in FIG. 3A and the like. As shownin FIG. 36, it is possible to switch the operation mode and the settingmode by depressing the SET key 42. For example, in the setting modeexplained above, when the SET key 42 is depressed in a state in whichregistration of a necessary image ends, the setting mode is switched tothe operation mode. In the setting mode, the SET key 42 is used in orderto instruct screen transition to, for example, shift the firstregistration screen to the second registration screen. It is possibleswitch the setting mode to the operation mode by depressing the SET key42 at a stage when final setting ends. In this way, means for screentransition in the setting mode and switching means from the setting modeto the operation mode are set as common operation, that is, thedepression of the SET key 42. Therefore, the user can perform necessarysetting by repeating work for pressing the SET key 42 and perform theswitching from the setting mode to the operation mode. Smooth settingwork is realized. Further, the switching from the setting mode to theoperation mode can be performed in common with final work in the settingmode. For example, in the three-point registration shown in FIG. 36, theSET key 42 is depressed on the first registration screen to register thenon-defective product image, the SET key 42 is depressed on the secondregistration screen to register the defective product image, the SET key42 is depressed on the third registration screen to register thebackground image. The switching work from the setting mode to theoperation mode is simultaneously executed. Consequently, the settingmode is automatically switched to the operation mode after the necessarysetting ends. Therefore, the user can smoothly perform the switchingfrom the setting work to the operation mode without being confused.

(Operation Mode Screen)

On the operation mode screen displayed on the display unit 43 in theoperation mode, the image display region PD and the explanation displayregion ED are provided. In the example shown in FIG. 36, the imagedisplay region PD is disposed on the left side of the display unit 43and the explanation display region ED is disposed on the right side.

(Common Position Display Function)

As display content of the display unit 43, layouts of the image displayregion PD and the explanation display region ED are desirably used incommon in the setting mode and the operation mode. In particular, when aregion where an image is displayed is set in a common position in thesetting mode and the operation mode, the user can check the imagewithout being confused. More specifically, when a region where a liveimage is displayed is fixed in a fixed position, the user can easilygrasp which image is a target image. In the example shown in FIG. 36, inboth of the setting mode and the operation mode, the image displayregion PD is fixed on the left side of the display unit 43. In this way,a relative positional relation is used in common during the setting andduring the operation. Therefore, it is possible to give security ofoperation to the user. On the second registration screen, the registeredfirst image and the live image serving as the candidate of the secondimage are displayed on one screen. However, if the live image is fixedon the left side, the user can recognize that the live image of theregistration target is on the left side of the common position and isless confused about which image is an image that should be registered.

The matching degree and the matching degree threshold are displayed onthe operation mode screen. Consequently, the user can check, on onescreen, a matching degree of an input image of sequentially imaged workand a non-defective product image calculated in the image and a matchingdegree threshold set in the setting mode.

A result of the pass/fail determination is output to the outside. Forexample, a signal indicating the determination result such as an OKsignal or an NG signal is transmitted. The determination result may bedisplayed on the outside. For example, the determination-result displaylamp 41 provided on the display surface 40 a of the image processingsensor shown in FIG. 3A and the like is lit according to thedetermination result.

Note that the pass/fail determination in this specification is used inmeaning including not only operation for determining whether theinspection target object is a non-defective product but also operationfor determining whether the inspection target object is a defectiveproduct. For example, the pass/fail determination includes, besides amode in which the pass/fail determining unit 57 d performs an outputwhen detecting a defective product and does not perform an output whilenot detecting a defective product, a mode in which the pass/faildetermining unit 57 d performs an output when detecting a non-defectiveproduct and does not perform the output while not detecting anon-defective product. An example of a flow of the operation in theoperation mode is shown in a flowchart of FIGS. 37A and 37B.

Note that the display of the display unit may be turned off in theoperation mode.

On the other hand, during the operation mode, the registration settingconditions can be changed according to, for example, a result of thepass/fail determination. For example, a set matching degree threshold isfinely adjusted to reduce wrong determination. In this case, theincrease/decrease adjusting unit 51 h used for the adjustment of theimage display magnification can also be used as a member for adjustingthe matching degree threshold. Consequently, the adjustment of the imagedisplay magnification and the adjustment of the matching degreethreshold are performed by the common member provided in the displayunit 43 to achieve simplification of a configuration and unity of anoperation environment. Such a procedure is explained with reference to aflowchart of FIGS. 38A and 38B. FIG. 38A is a flowchart for explainingthe operation of the setting mode including a step of adjusting imagedisplay magnification. FIG. 38B is a flowchart including a step ofadjusting a matching degree threshold in the operation mode followingFIG. 38A. First, in step S3800, the image processing sensor selects thesetting mode. Subsequently, in step S3801, the image processing sensorperforms capturing of images serving as candidates of a registrationtarget. Further, in step S3802, the image processing sensor performsupdate of the image displayed on the display unit 43.

As operation on the use side, the user checks the captured candidateimages with the display unit 43 and judges whether the candidate imagesare appropriate as a registration image. When adjustment of a postureand a visual field is necessary, the user performs appropriateprocessing according to adjustment. For example, when judging that theadjustment of the image display magnification is necessary, the useroperates the increase/decrease adjusting unit 51 h to adjust the displaymagnification.

As a result, as operation on the image processing sensor side, in stepS3804, the image processing sensor determines whether the up/down keys44, which are the increase/decrease adjusting unit 51 h, are operated.When the up/down keys 44 are operated, the image processing sensorproceeds to step S3805 and changes the setting to change the imagedisplay magnification according to the operation. When the ⇑ key 44 a,which is the switch on the up side, is operated, the image processingsensor increases the image magnification. Conversely, when the ⇓ key 44b, which is the switch on the down side, is operated, the imageprocessing sensor changes the setting to reduce the image magnification.The image processing sensor returns to step S3801, captures an imageagain at the changed magnification and causes the display unit 43 todisplay an image having the magnification after the change. Note that itis not always necessary to perform the capturing of an image again. Forexample, when increasing the magnification, the image processing sensormay perform digital zoom of the captured image and display the image.Conversely, when reducing the image, since a visual field displayed inthe image widens, it is necessary to acquire an image again. However,when images captured in the past are saved, the image processing sensormay be configured to call an image having relevant magnification.

In this way, an image having desired display magnification is obtained.When further magnification adjustment is unnecessary, the up/down keys44 are not operated instep S3803. Therefore, the image processing sensorproceeds to step S3805 and determines presence or absence of operationof the determination key. The image processing sensor determinespresence or absence of depression of the SET key 42, which is a mode ofthe determination key. When the SET key 42 is not depressed, the imageprocessing sensor returns to step S3804 and repeats the processing. Whenthe depression is detected, the image processing sensor proceeds to stepS3806 and registers a displayed image as a registration image. Further,in step S3807, the image processing sensor performs image registrationprocessing. Subsequently, as shown in FIG. 38B, the image processingsensor proceeds to step S3808 and switches the setting mode to theoperation mode. In step S3809, the image processing sensor captures animage of work serving as a target of the image processing, that is, thepass/fail determination. Subsequently, in step S3810, the imageprocessing sensor performs predetermined image processing and calculatesa degree of matching. In step S3811, the image processing sensorcompares the calculated matching degree with the matching degreethreshold, outputs a determination result, causes the display unit 43 todisplay a value of the calculated matching degree, and updates displaycontent of a live image displayed on the display unit 43 (step S3812).In step S3813, the image processing sensor determines presence orabsence of operation of the up/down keys 44, which are theincrease/decrease adjusting unit 51 h.

As operation on the user side, the user checks an obtained determinationresult, the input live image displayed on the display unit 43, and amatching degree calculated with respect to the input live image, andexamines whether the determination result is proper and whether thesetting of the matching degree threshold is appropriate. Whendetermining that a change of the matching degree threshold is necessary,the user operates the increase/decrease adjusting unit 51 h to finelyadjust the matching degree threshold.

As a result, as operation on the image processing sensor side, when theoperation of the up/down keys 44 is detected, the image processingsensor proceeds to step S3814 and changes the matching degree threshold.When the ⇑ key 44 a, which is the switch on the up-side, is operated,the image processing sensor increases the matching degree threshold.Conversely, when the ⇓ key 44 b, which is the switch on the down-side,is operated, the image processing sensor reduces the matching degreethreshold. The image processing sensor returns to step S3809 andperforms determination with the changed matching degree threshold. Theimage processing sensor repeats the operations according to necessity.When determining that an appropriate matching degree threshold is set,in step S3813, the image processing sensor does not detect the operationof the up/down keys 44. The image processing sensor proceeds to stepS3815 and determines presence of absence of stop operation of theoperation. The image processing sensor detects presence or absence ofoperation of the determination key. When the operation of thedetermination key is not detected, the image processing sensor returnsto step S3809 and repeats the processing explained above. On the otherhand, when the operation of the determination key is detected, the imageprocessing sensor proceeds to step S3816 and stops the operation mode.In this way, it is possible to perform fine adjustment to appropriatedisplay magnification and an appropriate matching degree threshold andimprove accuracy of the registration of an image and the pass/faildetermination. It is possible to use the increase/decrease adjustingunit 51 h common to these kinds of adjustment. In particular, in thesetting mode, an adjusting function for image display magnification isautomatically allocated to the increase/decrease adjusting unit 51 h. Onthe other hand, in the operation mode, the increase/decrease adjustingunit 51 h is changed to an adjusting function for the matching degreethreshold. The user obtains an advantage that the user can performnecessary setting simply by focusing on the operation of theincrease/decrease adjusting unit 51 h without performing operation forswitching of the functions of the increase/decrease adjusting unit 51 hand without being aware of the switching of the functions.

(Setting of a Resolution Reduction)

In the teaching in the setting mode of the two-point registration, thethree-point registration, the one-point registration, and the likeexplained above, it is possible to reduce image data in resolution inorder to increase the speed of arithmetic processing. It is possible toreduce image data in resolution and achieve an increase in the speed ofprocessing not only in the setting mode but also in the operation mode.According to a resolution reduction of an image, it is possible toreduce a data size and achieve a reduction of a load and an increase inthe speed of processing such as image processing. Depending on an image,it is also possible to reduce noise according to processing such ascompression and smoothing of the image. In performing such processing, aproblem is how to set a degree of the resolution reduction of the image.

Whereas a response time is sometimes set in the photoelectric sensor inthe past, an act of setting the response time is not assumed in theimage processing sensor. The response time indicates time required fromintrusion of the inspection target object into the imaging visual fieldof the imaging unit until the output of the determination result by thepass/fail determining unit. Even an image processing sensor thatspecifies a response time has a characteristic that the response time isdistinguished as a result of other set conditions such as a change inthe response time based on the visual field region set by the user. Theimage processing sensor is different from an image processing sensorthat optionally sets a response time. On the other hand, for example, ina manufacturing line of a factory, from the viewpoint of conveyancespeed and the like of the line, an image processing sensor is oftenrestricted by the presence of an inspection target object and a responsetime that can be consumed for the pass/fail determination. However, thevisual field and the response time cannot be directly set. This isbecause, since the resolution of a captured optical image directlychanges and jitter (fluctuation) occurs in the response time dependingon, for example, the setting of the visual field of the user, it isdifficult for the image processing sensor to specify the response time.On the other hand, the image processing sensor according to thisembodiment is configured to enable the response time to be setirrespective of the enlargement and reduction magnification anddetermine, on the basis of the set response time, image resolutionprocessed on the inside. The setting of a reduction in resolution isexplained in detail below with reference to FIGS. 39 and 40.

In the past, for the setting of the image processing sensor, the userneeds to, for example, set a light amount, adjust a visual field, andset image processing serving as a detection target (detection setting).States of operations processed on the inside of the image processingsensor with respect to user designation of the light amount setting, thevisual field adjustment, and the detection setting are shown in a blockdiagram of FIG. 39. As shown in the figure, as a result of the settingof the light amount by the user, an exposure time of the imaging unit 21is determined. As a result of the adjustment of the visual field,resolution of an optical image of an inspection target is determined.Further, as a result of setting of detection conditions, an algorithmused for the set image processing is determined. As a result, a timenecessary for imaging including a time required for readout of theoptical image, that is, an imaging time is determined from the exposuretime and the resolution of the imaging unit 21. On the other hand, atime required for the image processing, that is, an image processingtime is determined from the image resolution and the image processingalgorithm. A sum of the imaging time and the image processing time is aresponse time required for the processing. The response time isdetermined according to the order explained above.

On the other hand, from a relation of conveyance speed and the like ofthe manufacturing line, an allowable response time is sometimesdetermined in advance.In this case, setting itself is impossibledepending on setting content. For example, whereas the resolution isspontaneously determined according to the visual field setting of theuser, jitter occurs in the response time in which the resolutionchanges. It is difficult to specify the response time.

On the other hand, the image processing sensor according to thisembodiment can set the response time in addition to the visual field andthe detection setting. In order to realize the setting of the responsetime, registration setting conditions such as appropriate imageresolution and an image processing algorithm are determined by internalprocessing of the image processing sensor. Consequently, a data size ofa processed image is suppressed irrespective of the visual fieldsetting. The response time can be predefined. A state of the above isexplained with referenced to a block diagram of FIG. 40. As shown in thefigure, as items that the user can designate, in addition to lightamount setting, visual field adjustment, and detection purposes same asthose shown in FIG. 39, it is also possible to set the response time. Inresponse to such designation by the user, the condition allocating unit55 performs optimum allocation, determines an exposure time such thatprocessing ends within a designated response time, determinesresolution, and selects an appropriate image processing algorithm.

(Resolution Reduction of an Image)

A method of reducing the resolution of an image is explained. As amethod of changing resolution to be low, for example, as shown in FIG.41 with respect to a specified visual field range, there is a method ofcompressing image data as shown in FIG. 42. In an example shown in FIG.42, vertical and horizontal sizes are compressed to a half using a pixelvalue averaged in 2×2 pixels. Alternatively, as shown in FIG. 43, amethod of curtailing image data can also be used. In an example shown inFIG. 43, every other pixel values are adopted respectively in thevertical direction and the horizontal direction to compress vertical andhorizontal sizes to a half. In the present invention, the method ofreducing the image in resolution is not limited to the methods explainedabove. Known methods of reducing resolution can be adopted asappropriate. In order to realize the resolution reduction, there are amethod of using hardware such as a dedicated GPU and a method ofrealizing the resolution reduction with software. Both of the methodscan be used in the present invention. Alternatively, a combination ofthe methods may be used. In this specification, for convenience ofexplanation, the resolution reduction is sometimes collectively referredto as compression irrespective of methods such as compression andcurtailing.

(3′. Two-Point Registration of the Non-Defective Product Image and theBackground Image Including Resolution Reduction Processing)

A procedure in which the condition allocating unit 55 sets, on the basisof a set response time, registration setting conditions such as imagingconditions for an image, a compression degree, and an image processingalgorithm such that image capturing to the pass/fail determination canbe ended within the response time is explained. In the followingexplanation, the image-compression-degree setting unit 55 h of thecondition allocating unit 55 adjusts a compression ratio for reducing anoptical image in resolution among the registration setting conditions.First, a procedure of setting in the two-point registration includingthe resolution reduction processing and processing in the operation modeafter the setting in the two-point registration of the non-defectiveproduct image and the background image explained as 3 above is explainedwith reference to a flowchart of FIG. 44A.

(Setting of a Response Time)

First, in step S4401, a response time is set. Specifically, the usersets a desired response time from the response-time setting unit 51 e.The response-time setting unit 51 e desirably presents candidates of aplurality of different response times to the user in advance and urgesthe user to select a response time. By presenting, in advance, as aresponse time candidate group, response times that can be set, it ispossible to prepare, for each of the response times, combinations ofdetection conditions such as an exposure time, resolution (a compressionratio), and an image proceeding algorithm that can be set. It ispossible to reduce processing such as calculation in the conditionallocating unit 55. In other words, it is possible to quickly eliminate,according to the selected response time, detection conditions such as anexposure time that cannot be set among the registration settingconditions. For example, the image processing sensor causes the displayunit 43 to display “Sensor Setting” as a screen for performing settingof the image processing sensor in the setting mode for setting aresponse time, selects “Response Time”, which is a screen for setting aresponse time among items that can be set, and selects, for example, “20ms” as a specific response time. It is also possible to configure theimage processing sensor to, besides giving choices in advance as settingitems such as a response time, cause the user to directly input adesired response time as a numerical value or the like. In this case,the condition allocating unit 55 calculates, on the basis of the inputresponse time, a combination of detection conditions such as an exposuretime, resolution, and an image processing algorithm can that beselected.

Subsequently, in step S4402, the image processing sensor acquires anon-defective product image and a background image and saves thenon-defective product image and the background image in the imagestoring unit 54 i. Examples of optical images of the non-defectiveproduct image GDI and the background image BGI obtained in step S4402are respectively shown in FIGS. 44B and 44C.

Subsequently, in step S4403, the image processing sensor reduces thenon-defective product image GDI and the background image BGI inresolution on the basis of the response time set in step S4401. Theresolution reduction is performed by, for example, the image compressingunit 56 d. It is assumed that a compression degree is common to theimages. The image compressing unit 56 d compresses the non-defectiveproduct image GDI and the background image BGI. As a result, as shown inFIGS. 44D and 44E, the images are compressed and a compressednon-defective product image CGDI and a compressed background image CBGIhaving reduced image sizes are obtained.

Subsequently, in step S4404, the image processing sensor generates acompressed non-defective product-background differential image CG-CBDIfrom the compressed non-defective product image CGDI and the compressedbackground image CBGI. The generation of the compressed non-defectiveproduct-background differential image CG-CBDI is performed by, forexample, the differential-image generating unit 56 a. The compressednon-defective product-background differential image CG-CBDI obtained bythe differential-image generating unit 56 a is as shown in FIG. 44F.

In step S4405, the image processing sensor sets an evaluation region.The evaluation region may be set as, for example, the entire image. Aregion near the center, a region where the differential image ispresent, or the like may be automatically set on the image processingsensor side. Alternatively, the user may manually designate theevaluation region. When the user manually designates the evaluationregion, for example, an evaluation-region setting unit is provided inthe operation unit 51 shown in FIG. 4.

Subsequently, in step S4406, the image processing sensor extractsoptimum feature values of the non-defective product image. Theextraction of the feature values is performed by, for example, thefeature-value extracting unit 56 b.

Further, in step S4407, the image processing sensor determines amatching degree threshold. For example, the threshold calculating unitevaluates a matching degree with the background image on the basis ofthe extracted feature values of the non-defective product image todetermine the matching degree threshold.

(Operation Mode)

When the setting work in the setting mode ends as explained above, thesetting mode is switched to the operation mode. Subsequently, theoperation procedure in the operation mode is continuously explained withreference to FIG. 44A. In step S4408, the image processing sensoracquires, with the imaging unit 21, an input live image of work servingas an evaluation target. Subsequently, in step S4409, the imageprocessing sensor reduces the input live image of the evaluation targetin resolution. A compression degree of the input live image is set equalto a compression degree of an image in the setting mode. Further, instep S4410, the image processing sensor calculates a matching degree ofthe work on the basis of the feature values of the non-defective productimage registered in the setting mode, compares the matching degree withthe matching degree threshold, and performs the pass/fail determination.In this way, it is possible to perform the setting according to the setresponse time to reduce the resolution and perform the processing in theoperation mode within the designated response time.

(3″. Modification of the Two-Point Registration of the Non-DefectiveProduct Image and the Background Image Including the ResolutionReduction Processing)

In the example explained above, the method of setting the matchingdegree threshold in the order of performing the resolution reductionfirst during the setting and then generating the differential image isexplained. However, the present invention does not limit order ofsetting the matching degree threshold to the order explained above. Forexample, an image may be compressed after a differential image isgenerated first. Such an example is explained as a modification belowwith reference to a flowchart of FIG. 45A. First, in step S4501, aresponse time is set. Subsequently, in step S4502, the image processingsensor acquires the non-defective product image GDI and the backgroundimage BGI and saves the non-defective product image GDI and thebackground image BGI in the image storing unit 54 i. These steps are thesame as steps S4401 and S4402 in FIG. 44A explained above. Thenon-defective product image GDI and the background image BGI shown inFIGS. 45B and 45C are respectively acquired.

Subsequently, in step S4503, the image processing sensor generates anon-defective product-background differential image from thenon-defective product image GDI and the background image BGI. As aresult, a non-defective product-background differential image G-BDIshown in FIG. 45D is generated by the differential-image generating unit56 a. In step S4504, the image processing sensor reduces thenon-defective product-background differential image G-BDI in resolutionaccording to the response time setting. It is assumed that compressiondegrees of the images in reducing the resolution in the imagecompressing unit 56 d are common. As a result, a compressednon-defective product-background differential image CG-CBDI, which is aresolution-reduced image of the non-defective-product-backgrounddifferential image G-BDI, shown in FIG. 45E is obtained by the imagecompressing unit 56 d.

Thereafter, as in steps S4405 to S4410 in FIG. 44A explained above, theimage processing sensor sets an evaluation region in step S4505,extracts appropriate feature values of the non-defective product imagein step S4506, and sets a matching degree threshold in step S4507. Theimage processing sensor switches the setting mode to the operation modeafter the end of the setting mode. The image processing sensor acquiresan input live image serving as an evaluation target in step S4508 andreduces the input live image in resolution in step S4509. A compressiondegree of the input live image is set equal to the compression degree ofthe image in the setting mode. In step S4510, the image processingsensor performs the pass/fail determination. In this method, as in themethod explained above, it is possible to reduce the differential imagein resolution and adjust the image processing time according to the setresponse time.

(1′. Procedure of Three-Point Registration of the Non-Defective ProductImage, the Defective Product Image, and the Background Image Includingthe Resolution Reduction Processing)

The example is explained above in which the resolution reductionprocessing is added in the two-point registration. The example isexplained in which the non-defective product image and the backgroundimage are registered. However, the resolution reduction processing canalso be added in the two-point registration for registering thenon-defective product image and the defective product image. Further,the resolution reduction processing may be added in three-pointregistration as well. An example in which the resolution reductionprocessing is added in three-point registration for registering thenon-defective product image, the defective product image, and thebackground image is explained below with reference to a flowchart ofFIG. 46A. First, in step S4601, a response time is set. Subsequently, instep S4602, the image processing sensor acquires a non-defective productimage, a defective product image, and a background image. The imageprocessing sensor captures the images with the imaging unit 21. Theimage processing sensor acquires the non-defective product image GDI,the defective product image NGI, and the background image BGIrespectively shown in FIGS. 46B, 46C, and 46D and saves the images inthe image storing unit 54 i. Subsequently, instep S4603, the imageprocessing sensor reduces the non-defective product image GDI, thedefective product image NGI, and the background image BGI in resolutionaccording to the response time setting. The compressed non-defectiveproduct image CGDI, the compressed defective product image CNGI, and thecompressed background image CBGI compressed by the image compressingunit 56 d are respectively as shown in FIG. 46E, FIG. 46F, and FIG. 46G.It is assumed that a compression degree is common to the images.

Subsequently, in step S4604, the image processing sensor generates, withthe differential-image generating unit 56 a, the compressednon-defective-product-background differential image CG-CBDI, which isthe differential image between the compressed non-defective productimage CGDI and the compressed background image CBGI, and a compresseddefective product-background differential image CN-CBDI, which is thedifferential image between the compressed defective product image CNGIand the compressed background image CBGI. The compressednon-defective-product-background differential image CG-CBDI and thecompressed defective product-background differential image CN-CBDIgenerated by the differential-image generating unit 56 a arerespectively as shown in FIG. 46H and FIG. 46I.

In step S4605, the image processing sensor sets evaluation regionsrespectively in the differential images obtained in this way. Further,in step S4606, the image processing sensor extracts feature valuesrespectively from the evaluation regions of the differential images.Specifically, the image processing sensor extracts, with thefeature-value extracting unit 56 b, feature values of the non-defectiveproduct image from the compressed non-defective-product-backgrounddifferential image CG-CBDI and extracts, with the feature-valueextracting unit 56 b, feature values of the defective product image fromthe compressed defective product-background differential image CN-CBDI.In step S4607, the image processing sensor sets a matching degreethreshold. The threshold calculating unit evaluates a matching degree ofthe defective product image on the basis of the feature values of thenon-defective product image to thereby set the matching degreethreshold.

When the setting ends in this way, the image processing section isshifted from the setting mode to the operation mode. In the operationmode, in step S4608, the image processing sensor acquires an input liveimage of an evaluation target. In step S4609, the image processingsensor reduces the acquired input live image in resolution. Acompression degree of the input live image is set equal to a compressiondegree of an image in the setting mode. In step S4610, the imageprocessing sensor performs the pass/fail determination. The imageprocessing sensor calculates a matching degree of the input live imageon the basis of the feature values of the non-defective product image.The pass/fail determining unit 57 d compares the matching degree withthe matching degree threshold to perform the pass/fail determination andoutputs a determination result.

In this way, in the three-point registration, as in the two-pointregistration, by adding the resolution reduction processing, it ispossible to end the image processing within the set response time. It ispossible to realize the image processing sensor corresponding to inlineprocessing.

(1″. Modification of the Three-Point Registration of the Non-DefectiveProduct Image, the Defective Product Image, and the Background ImageIncluding the Resolution Reduction Processing)

The example in which the resolution reduction processing is added in thethree-point registration is explained above. In this example, thematching degree threshold is set in the order of performing theresolution reduction first during the setting and then generating thedifferential image. However, as explained in the two-point registration,the present invention does not limit order of setting the matchingdegree threshold to this order. In the three-point registration, as inthe two-point registration, an image may be compressed after adifferential image is generated first. Such an example is explainedbelow with reference to a flowchart of FIG. 47A. First, in step S4701, aresponse time is set. Subsequently, in step S4702, the image processingsensor acquires a non-defective product image, a defective productimage, and a background image and saves the images in the image storingunit 54 i. These steps are the same as the steps S4601 and S4602 in FIG.46A. The non-defective product image GDI, the defective product imageNGI, and the background image BGI respectively shown in FIGS. 47B, 47C,and 47D are acquired.

Subsequently, in step S4703, the image processing sensor generates thenon-defective product-background differential image G-BDI from thenon-defective product image GDI and the background image BGI andgenerates the defective product-background differential image N-BDI fromthe defective product image NGI and the background image BGI. As aresult, the non-defective product -background differential image G-BDIand the defective product-background differential image N-BDIrespectively shown in FIGS. 47E and 47F are obtained. In step S4704, theimage processing sensor reduces the non-defective product-backgrounddifferential image G-BDI and the defective product-backgrounddifferential image N-BDI in resolution according to the response timesetting. It is assumed that compression degrees of the images inreducing the resolution in the image compressing unit 56 d are common.As a result, the compressed non-defective product-backgrounddifferential image CG-CBDI and the compressed defectiveproduct-background differential image CN-CBDI, which areresolution-reduced images of the non-defective product-backgrounddifferential image G-BDI and the defective product-backgrounddifferential image N-BDI, respectively shown in FIGS. 47G and 47H areobtained.

Thereafter, as in steps S4605 to S4610 in FIG. 46A explained above, theimage processing sensor sets an evaluation region in step S4705,extracts appropriate feature values of the non-defective product imageand appropriate feature values of the defective product image in stepS4706, and sets a matching degree threshold on the basis of the featurevalues in step S4707. The image processing sensor switches the settingmode to the operation mode after the end of the setting mode. The imageprocessing sensor acquires an input live image serving as an evaluationtarget in step S4708 and reduces the input live image in resolution instep S4709. A compression degree of the input live image is set equal tothe compression degree of the image in the setting mode. In step S4710,the image processing sensor performs the pass/fail determination. Inthis method, as in the methods explained above, it is possible to reducethe differential image in resolution and adjust the image processingtime according to the set response time.

(1′. Procedure of the One-Point Registration of the Background ImageIncluding the Resolution Reduction Processing)

Further, the resolution reduction processing can be added in theone-point registration as well. Such an example is explained withreference to a flowchart of FIG. 48A. First, in step S4801, a responsetime is set. Subsequently, in step S4802, the image processing sensoracquires a background image. Consequently, the background image BGIshown in FIG. 48B is captured and saved in the image storing unit 54 i.Subsequently, in step S4803, the image processing sensor reduces thebackground image BGI in resolution according to the response timesetting. Consequently, the compressed background image CBGI shown inFIG. 48C is obtained. Subsequently, in step S4804, the image processingsensor sets an evaluation region. The entire region of the compressedbackground image CBGI is set as the evaluation region. In step S4805,the image processing sensor extracts feature values of the compressedbackground image CBGI. Further, in step S4806, the image processingsensor calculates a matching degree threshold. For example, thethreshold calculating unit uniformly sets the matching degree thresholdto a matching degree of 50%.

When the setting ends in this way, the image processing sensor isswitched from the setting mode to the operation mode. In the operationmode, first, in step S4807, the image processing sensor acquires aninput live image of an evaluation target. Subsequently, in step S4808,the image processing sensor reduces the input live image in resolution.A compression degree of the input live image is set equal to thecompression degree of the image in the setting mode. In step S4809, theimage processing sensor performs the pass/fail determination. The imageprocessing sensor calculates, with the matching-degree calculating unit57 c, a matching degree of the input live image on the basis of thefeature values of the background image. The pass/fail determining unit57 d compares the matching degree with the matching degree threshold andperforms the pass/fail determination. In this way, it is possible to addthe resolution reduction processing in the one-point registration aswell and perform the image processing within the set response time.

In the example explained above, the image-compression-degree settingunit of the condition allocating unit adjusts the compression degree forreducing the image in resolution as a registration setting conditionsuch that the processing can be ended within the set response time.However, the present invention does not limit the registration settingcondition adjusted by the condition allocating unit to the compressiondegree of the image. The registration setting condition can be otherconditions such as imaging conditions for an image captured by theimaging unit and conditions of image processing. An example is explainedbelow in which the condition allocating unit adjusts imaging conditions.

(Imaging-Condition Allocating Unit)

Ranges of imaging conditions that can be adopted as the registrationsetting conditions are determined according to the set response time. Itis assumed that imaging conditions for an image are adjusted withrespect to a response time. In this case, the condition allocating unit55 functions as the imaging-condition allocating unit 55 d capable ofadjusting imaging conditions for an image captured by the imaging unitsuch that it is possible to perform predetermined image processing forperforming the pass/fail determination within a response time.

(Imaging Conditions)

Examples of the imaging conditions include adjusting an exposure timeduring imaging by the imaging unit and a light amount (illuminationintensity) of illumination light in order to adjust brightness of animage. A gain (e.g., a digital gain value for specifying how many foldsthe brightness of a CMOS, which is an imaging element, is increased) ofthe imaging unit, presence or absence a polarization filter, a change inan illumination color, and the like may be included in the imagingconditions. Alternatively, when the imaging unit has a high dynamicrange image generating function for combining a plurality oflow-gradation images captured by changing a dynamic range of a luminanceregion to form a high-gradation image, ON/OFF of the HDR function may beincluded in the imaging conditions. Further, besides parameters duringimaging such as ON/OFF of an automatic brightness adjusting function, apixel skip and curtaining function for increasing a frame rate, a nearpixel totalizing and outputting function, and the like and an angle(±180°, etc.) of rotation and inclination, parameters and the like inprocessing obtained image data can be included in the imagingconditions.

In the following explanation, as a form of the imaging-conditionallocating unit 55 d, a procedure in which the brightness-conditionallocating unit 55 e, that is, the brightness-condition-candidatesetting unit 55 f and the brightness-condition selecting unit 55 gadjust the brightness of an image and determine an optimum brightnesscondition is explained with reference to FIG. 49A. First, theresponse-time setting unit 51 e sets a response time.

(Determination of Brightness Conditions)

The brightness-condition-candidate setting unit 55 f and thebrightness-condition selecting unit 55 g determine brightness conditionsas the registration setting conditions according to the set responsetime. In an example shown in FIG. 49A, an example of the two-pointregistration of the non-defective product image and the background imageis shown. First, the brightness-condition-candidate setting unit 55 fallocates a respective plurality of brightness conditions as brightnesscondition candidates on the basis of the response time set by theresponse-time setting unit 51 e such that a determination result by thepass/fail determining unit 57 d is output within the response time. Thatis, an upper limit and a lower limit of an imaging time required forimaging per one image, which can be set by the imaging unit 21, aredetermined according to the performance, the specification, and the likeof an apparatus. On the other hand, an upper limit of the imaging timeallowed within the response time is determined from the response timeset by the response-time setting unit 51 e. In this way, an allowableimaging time is determined from the physical specifications of theimaging unit 21 and the given response time. In the imaging time, whentransfer and processing abilities of an image are considered to befixed, an exposure time is a parameter that can be set. A lower limit ofthe exposure time that can be set is also determined from thespecifications and the like. Therefore, a range of time that can betaken as the exposure time is determined. Therefore, the allowableexposure time is changed and a plurality of brightness conditions areset as brightness condition candidates. Specifically, thebrightness-condition-candidate setting unit 55 f extracts brightnesscondition candidates that can be taken within the range of the allowableexposure time. For example, the range of the allowable exposure time isequally divided by a predetermined number (e.g., five) to set theexposure time. Alternatively, all exposure times that can be set byspecifiable width (e.g., 10 ms) are extracted as the brightnesscondition candidates. In the example shown in FIG. 49A, thebrightness-condition-candidate setting unit 55 f sets n brightnesscondition candidates 1 to n. Note that the brightness conditioncandidates do not always need to be set at equal intervals. For example,the brightness condition candidates may be densely set in a range inwhich appropriate brightness can be expected.

(Acquisition of a Candidate Image Group)

Candidate images are acquired for each of a plurality of differentbrightness condition candidates. The image-group acquiring unit 52 acontrols the imaging unit 21 to capture a plurality of candidate images.The candidate images to be captured are determined according to thesetting mode. For example, the image-group acquiring unit 52 a capturesnon-defective product candidate images and background candidate imagesin the two-point registration in which the non-defective product imageand the background image are used, captures non-defective productcandidate images and defective product candidate images in the two-pointregistration in which the non-defective product image and the defectiveproduct image are used, captures non-defective product candidate images,defective product candidate images, and background candidate images inthe three-point registration, and captures background candidate imagesin the one-point registration. As explained above, the image-groupacquiring unit 52 a urges the user to dispose work for each of theimages to be captured. For example, the image-group acquiring unit 52 aperforms guidance display on the display unit 43. When the work is set,the image processing sensor changes the brightness conditions andcaptures candidate images for each of the brightness conditioncandidates. Note that setting of the plurality of different brightnesscondition candidates and work for capturing the candidate images foreach of the brightness condition candidates are automatically performed.The user only has to set the work in the screen visual field and removesthe work according to guidance in the setting mode without being awareof such setting work. In the example shown in FIG. 49A, in order toperform the two-point registration of the non-defective product imageand the background image, the image processing sensor instructs the userto place non-defective work in the screen visual field. A plurality ofnon-defective product candidate images are captured for each of thedifferent bright condition candidates in a state in which thenon-defective work is placed according to the instruction. After thecapturing of the non-defective product candidate images, the imageprocessing sensor instructs the user to remove the non-defective work. Aplurality of background candidate images are captured in a state inwhich the user removes the non-defective work according to theinstruction. Note that, in the case of the three-point registration, inaddition to the above, guidance for instructing the user to placedefective work in the screen visual field and work for imaging, for eachof the brightness condition candidates, the defective work placed in thescreen visual field according to the guidance and capturing defectiveproduct candidate images are added.

(Generation of Differential Candidate Images)

Differential candidate images are generated from the acquired candidateimages. The differential-image generating unit 56 a generatesdifferential candidate images from a pair of candidate images capturedunder the same brightness condition candidate. In the example shown inFIG. 49A, the differential-image generating unit 56 a generatesnon-defective product-background differential candidate images from thenon-defective candidate images and the background candidate images. Notethat, in the case of the three-point registration, in addition to theabove, work for generating defective product-background differentialcandidate images from the defective product candidate images and thebackground candidate images is added.

Note that the differential image and the original image before thedifferential image generation can be compressed. In this case, theimage-compression-degree setting unit 55 h adjusts an image compressiondegree within a given condition.

(Execution of Image Processing: Optional)

The image processing sensor performs predetermined image processing onthe differential candidate images according to necessity. The imageprocessing is set in advance as image processing included in theregistration setting conditions. The image processing is performed inthe image-processing executing unit.

(Allocation of Image Processing Content)

A processing flow of the predetermined image processing performed inorder to perform the pass/fail determination of an inspection targetobject is not limited to one processing flow and can be configured by aplurality of different processing flows. The image-processing-conditionallocating unit 55 i explained below allocate conditions of thepredetermined image processing to each of the plurality of differentprocessing flows. For example, concerning the image processing flow, byallocating the conditions of the image processing, it is possible toevaluate a matching degree calculated from candidate images after theimage processing to select optimum image processing. Examples of theconditions of the image processing include a type of a processing moduleconfiguring the processing flow of the predetermined image processingand/or image processing parameters referred to in the processing flow.When the conditions of the image processing are allocated, imageprocessing condition candidates are generated by theimage-processing-condition allocating unit 55 i. Theimage-processing-condition allocating unit 55 i is configured to changethe processing module and at least a part of the image processingparameters and allocate the conditions of the predetermined imageprocessing.

(Calculation of a Matching Degree)

Matching degrees are calculated by the matching-degree calculating unit57 c respectively with respect to the differential candidate imagessubjected to the image processing according to necessity. Thematching-degree calculating unit 57 c can be configured to calculate amatching degree for each of a plurality of different processing flows.In the example shown in FIG. 49A, the matching-degree calculating unit57 c respectively calculates matching degrees of background candidateimages with respect to model images corresponding to the obtainednon-defective product-background differential candidate images. Notethat, in the case of the three-point registration, the matching-degreecalculating unit 57 c calculates matching degrees of defectiveproduct-background differential candidate images with respect to themodel images corresponding to the non-defective product-backgrounddifferential candidate images.

(Selection of a Brightness Condition)

In a state in which the matching degree is obtained for each of thebrightness condition candidates in this way, the image processing sensorselects, with the brightness-condition selecting unit 55 g, appropriatebrightness conditions according to a selection condition. In the exampleshown in FIG. 49A, the image processing sensor evaluates brightnessconditions using matching degrees of the non-defectiveproduct-background differential candidate images and the backgroundcandidate images as evaluation values serving as the selectioncondition. Not that, in the case of the three-point registration, theimage processing sensor evaluates the brightness conditions usingmatching degrees of the non-defective product-background differentialcandidate images and the defective product-background differentialcandidate images as evaluation values. The brightness-conditionselecting unit 55 g selects, for example, out of a plurality ofbrightness condition candidates, a brightness condition candidate havingthe lowest matching degree as an optimum brightness condition. Byselecting the brightness condition having the lowest matching degree, inthe operation mode, the lowest matching degree is further separated froma high matching degree with the non-defective product image. It iseasier to set a matching degree threshold.

However, the selection condition is not limited to the lowest matchingdegree. That is, it is not always necessary to select the brightnesscondition having the lowest matching degree as the optimum brightnesscondition. The optimum brightness condition can also be determinedtaking into account a difference from an adjacent matching degree. Forexample, as shown in Table 2, when a matching degree is calculated foreach of the brightness condition candidates, the matching degree is amatching degree of 40% at the time of a brightness condition 7 accordingto the lowest matching degree. However, in this case, a difference in amatching degree is large between the brightness condition candidate andan adjacent brightness condition candidate. This indicates that anevaluation value fluctuates when the brightness of illumination changeseven a little. In other words, it is surmised that resistance againstfluctuation in ambient brightness is weak. On the other hand, if thematching degree is a matching degree of 45% at the time of a brightnesscondition candidate 3, which is a second lowest matching degree, adifference is relatively small between the brightness conditioncandidate and the adjacent brightness condition candidate. Consequently,it can be evaluated that the resistance against fluctuation inbrightness is excellent. It is evaluated that the brightness conditiondeserves to be adopted as the appropriate brightness condition. In thisway, it is desirable to take into account, as the selection conditionfor selecting brightness condition candidate, in addition to the lowmatching degree of the brightness condition candidate, a relativelysmall difference from a matching degree of a brightness conditioncandidate near the brightness condition candidate.

TABLE 2 Brightness condition Matching degree 1 55 2 50 3 45 4 50 5 55 665 7 40 8 65

(Image-Processing-Condition Allocating Unit 55 i)

In the example explained above, the procedure for changing thebrightness conditions of the image as the imaging conditions andselecting the optimum brightness conditions is explained. As explainedabove, the condition allocating unit can adjust image processingconditions in addition to such imaging conditions and the compressiondegree of the image. The image processing conditions include a type ofan image processing algorithm to be selected and adjustment of imageprocessing parameters of the selected image processing algorithm. When acondition of the image processing algorithm is changed or adjusted, thecondition allocating unit functions as the image-processing-conditionallocating unit 55 i for changing the conditions of the image processingalgorithm executed in the image processing such that a determinationresult by the pass/fail determining unit 57 d is output within aresponse time. Consequently, it is possible to change a processing loadof image processing used for the pass/fail determination to anappropriate load within a response time desired by the user. It ispossible to end the image processing within a given time to cope withinline processing and the like.

A procedure in which the condition allocating unit 55 adjusts the imageprocessing conditions as the registration setting conditions accordingto a response time set by the response-time setting unit 51 e isexplained. Besides capturing only one optical image with the imagingunit and registering the image in the setting mode, it is also possibleto, for each of a plurality of candidate registration setting conditionswith registration setting conditions varied, capture images as candidateimages and retain the images, select an image suitable for registrationout of these plurality of candidate images, and set the image as aregistration image. A procedure in which the condition allocating unit55 captures a plurality of candidate images under a plurality ofdifferent candidate registration setting conditions, selects optimumregistration setting conditions suitable for the pass/fail determinationamong the candidate registration setting conditions, and registers acandidate image obtained under the conditions as a registration image isexplained with reference to Tables 3 and 4.

A time that can be consumed for capturing of an optical image isspontaneously decided at a stage when the response time is set by theresponse-time setting unit 51 e. That is, an image is captured withinthe response time, compressed, and subjected to differential processingaccording to necessity, feature values are calculated, and the pass/faildetermination is performed. Therefore, a time allocated to the imagingis limited to a fixed time within the given response time. Therefore, anupper limit of the imaging time is determined according to the responsetime, that is, an upper limit of an exposure time during the imaging isalso determined. A range of an exposure time that can be set isdetermined according to specifications of hardware such as an imagingelement and a camera and software used in the imaging unit 21.Therefore, taking these into account, according to the given responsetime, an exposure time selectable in the response time is determinedwithin the exposure time that can be set on the imaging unit 21 side inadvance. In this way, the condition allocating unit 55 determines acombination of selectable exposure times according to the response time.For example, when a plurality of sets of exposure times are provided inadvance, the condition allocating unit 55 extracts a combination ofselectable exposure times.

When the response-time setting unit 51 e is configured to cause the userto select the response time from a plurality of response time candidategroups prepared in advance rather than any numerical values, acombination of selectable exposure times is determined for each of theresponse time candidates. Therefore, it is also possible to prepare theexposure times as a table or the like in advance such that a candidategroups of exposure times is automatically extracted according toselection of the response time candidates. With this method, it ispossible to reduce processing that should be performed on the conditionallocating unit 55 side and realize more inexpensive, lighter-load, orhigher-speed processing.

An example of a combination of exposure times with respect to a responsetime is shown in Table 3. In this way, the number of selectable exposuretimes increases as the response time is longer. Note that, even aftercapturing of an image, other processing such as compression of theimage, differential processing, and distinction processing is necessary.Therefore, as explained above, the entire response time cannot beconsumed for the exposure times.

As the registration setting conditions, besides the imaging conditionsfor an image such as the exposure time, instead of or in addition to theimaging conditions, conditions of image processing, a compression degree(resolution) of the image can also be applied. As an example, acombination of an image processing algorithm and resolution with respectto a response time is shown in Table 4. As shown in the table, there areSearch and Holistic as an evaluation method for evaluating whethernon-defective work specified by differential processing with abackground image is present in an operation image. The Search is amethod of specifying, from the operation image, a position in a screenof the non-defective work through a pattern search and evaluating amatching degree. On the other hand, the Holistic is a method ofidentifying the position of the work through comparison of featurevalues (e.g., a luminance average, contrast, and the number of edgepixels) extracted from the entire image without performing the positionspecifying processing for the work from the operation image. TheHolistic is called overall evaluation as well.

As the Search, there are Search[A], which is a normalized correlationsearch, for performing a search with a pixel value and Search [B] forperforming a search by geometrical information such as a contour. Whencomparison by an edge feature, which is one of specific feature, isperformed in the Holistic, there are Holistic[A] for extracting an edgewith a Roberts operator and Holistic[B] for extracting an edge with aSobel operator. Even if the Search[A] and the Search[B] and theHolistic[A] and the Holistic[B] have the same “resolution and Search”and the same “resolution and Holistic”, differences occur in aprocessing time, identification performance, an operationcharacteristic, and the like because of processing on the inside. A{grave over (p)}arameter equivalent to a rotation allowable angle can beincluded in the image processing during an image search.

In the example shown in Table 4, both of the image processing algorithmand the resolution are adjusted with respect to the response time.However, the present invention is not limited to this. The exposuretime, the image processing algorithm, and the resolution can also beadjusted with respect to the response time. As an example, in Table 5, aselectable combination of the exposure time, the image processingalgorithm type, and the resolution at the time when the response time(for example, 20 ms) is given is shown. In the table, a circle indicatesa selectable combination, a cross indicates an unselectable combinationbecause of the response time, and a cross with half-tone dot meshingindicates an unselectable combination in the combination of the exposuretime, the image processing algorithm, and the resolution.

As explained above, a candidate group of selectable registration settingconditions is determined according to the response time. The imageprocessing sensor selects, with the condition allocating unit 55,desirable registration setting conditions out of the candidate group. Asexplained above, the desirable registration setting conditions areconditions under which a non-defective product and a defective productcan be surely distinguished when the pass/fail determination isperformed in the operation mode. The pass/fail determining unit 57 dperforms the pass/fail determination using a matching degree with thenon-defective product as an evaluation value. In order to stablyseparate the non--defective product and the defective product, that is,in order to separate the non-defective product and the defective productas much as possible and set, with the threshold calculating unit, amatching degree threshold in the middle of the non-defective product andthe defective product, the registration setting conditions are desirablyconditions under which a matching degree with the defective product iscalculated as low as possible. Therefore, it is important for thecondition allocating unit 55 to obtain registration setting conditionsthat can achieve such a good registration state, for example, acombination of the exposure time, the resolution, and the imageprocessing algorithm.

Note that, in the example explained above, the user can designate theresponse time from the response-time setting unit. However, the presentinvention is not limited to this configuration. The response time can bea fixed value. In this case, the response time is given as a defaultfixed value. Therefore, in FIG. 40, the response time is a defaultresponse time. An upper limit of the imaging time, that is, a maximumimaging time is unconditionally determined on the basis of the defaultresponse time. Therefore, the condition allocating unit 55 allocates theregistration setting conditions such as imaging conditions of an image,a compression degree of a captured image, and an image processingalgorithm within a range of the maximum imaging time. Such a procedureis explained with reference to FIG. 49B. Compared with FIG. 49A, in astate shown in FIG. 49B, the response-time setting unit is absent. Theresponse time is given as a default fixed value. Therefore, on the basisof an allowable maximum exposure time unconditionally determined fromthe default response time, the brightness-condition-candidate settingunit 55 f sets brightness conditions and the image-processing-conditionallocating unit 55 i sets image processing. Alternatively, theimage-compression-degree setting unit 55 h adjusts an image compressiondegree. A specific flow of processing is the same as the flow explainedabove.

(Determination of Optimum Registration Setting Conditions)

A procedure in which the condition allocating unit 55 finds appropriateregistration setting conditions from such a candidate group ofregistration setting conditions and performs image registration isexplained with reference to a flowchart of FIG. 50. First, in stepS5001, a response time is acquired. A response time set for the user ora response time of a fixed value set in advance is acquired from theresponse-time setting unit 51 e.

Subsequently, in step S5002, the condition allocating unit 55 extractscandidate registration setting conditions according to the responsetime. As the candidate registration setting conditions, changeableparameters are decided in advance. For example, when an exposure time,resolution, and an image processing algorithm can be adjusted, thecondition allocating unit 55 extracts, according to the response timeset in step S5001, a combination of an exposure time, resolution, and animage processing algorithm that can be combined is extracted. In thiscase, combinations of exposure times, resolutions, image processingalgorithms that can be set can be prepared as a candidate registrationsetting condition table with respect to designated response time inadvance and saved in the setting saving unit 54 d. Consequently, byreferring to the candidate registration setting condition table, thecandidate registration setting conditions including the exposure time,the resolution, and the image processing algorithm that can be set areextracted according to the set response time. In the following steps,images are captured for each of the extracted candidate registrationsetting conditions, matching degrees are respectively evaluated, andoptimum registration conditions are selected out of the obtainedmatching degrees.

Specifically, first, in step S5003, the condition allocating unit 55determines whether unevaluated candidate registration setting conditionsare present. In a first loop, imaging and an evaluation under thecandidate registration setting conditions are not performed yet.Therefore, the condition allocating unit 55 proceeds to step S5004,actually captures an optical images for each of the candidateregistration setting conditions, and calculates a matching degree.Specifically, in step S5004, the condition allocating unit 55 performscapturing of optical images to image processing on the basis of theunevaluated candidate registration setting conditions and calculates amatching degree. This step is the same as the steps in the registrationprocessing during the setting in FIGS. 44A, 45A, 46A, 47A, and 48A andthe like explained above. That is, any one of the two-pointregistration, the three-point registration, and the one-pointregistration may be used. Further, in order to eliminate a waste ofrepeating imaging many time under the same imaging conditions (e.g.,exposure time), it is also possible to save images as appropriate andread and process the saved images in the case of the same imagingconditions.

Subsequently, in step S5005, the condition allocating unit 55 determineswhether an evaluation value of the obtained matching degree is theminimum. Since an evaluation value is not saved in the first loop, theevaluation value of the obtained matching degree is a minimum value.Therefore, the condition allocating unit 55 proceeds to step S5006,saves the evaluation value at this point and the candidate registrationsetting conditions under which the evaluation value is obtained, returnsto step S5003, and repeats the processing. Thereafter, the conditionallocating unit 55 performs imaging and image processing under newcandidate registration conditions in the same manner, acquires anevaluation value, and determines instep S5005 whether the evaluationvalue is a minimum value. When the evaluation value is not the minimumvalue, the condition allocating unit 55 returns to step S5003 andrepeats the evaluation under the next candidate registration settingconditions. On the other hand, when the evaluation value is the minimumvalue, the condition allocating unit 55 proceeds from step S5005 to stepS5006, updates the minimum evaluation value and the candidateregistration setting conditions at that point, and then returns to stepS5003 and repeats the evaluation. When the evaluation of all thecandidate registration setting conditions ends in this way, thecondition allocating unit 55 proceeds from step S5003 to step S5007 andsets, as registration setting conditions, the candidate registrationsetting conditions under which the evaluation value is the minimum. Inthis way, the condition allocating unit 55 can determine optimumregistration setting conditions under which a matching degree of adefective product is the lowest out of the candidate registrationsetting conditions that can be set in the designated response time.

Note that the meaning of “unevaluated” is explained. For example, it isassumed that, in the three-point registration, an exposure time ischanged in ten stages and thirty images in total, that is, tennon-defective product images, ten defective product images, and ten background images are captured. In a first loop of step S5003, the conditionallocating unit 55 selects an exposure time of 1/10, acquires anon-defective product image, a defective product image, and a backgroundimage at the exposure time in step S5004, and thereafter performs theevaluation. In a second loop of step S5003, since the evaluation isalready performed concerning the exposure time of 1/10, the conditionallocating unit 55 selects, for example, 2/10 among the remainingexposure times and performs the acquisition and the evaluation of animage in the exposure time. Further, in a third loop of step S5003, thecondition allocating unit 55 further selects another exposure time,performs the same evaluation, thereafter sequentially changes theexposure time, and performs the evaluation concerning all the exposuretimes.

An example in which the image-processing-condition allocating unit 55 iconfiguring the condition allocating unit 55 replaces an imageprocessing algorithm in predetermined image processing is explained withreference to flowchart of FIGS. 51A to 51B. It is assumed that thenon-defective product image GDI shown in FIG. 51C, the defective productimage NGI shown in FIG. 51D, and the background image BGI shown in FIG.51E are registered in the setting mode and an input image shown in FIG.51F is obtained in the operation mode. As shown in the flowchart of FIG.51A, the image processing is processed in the order of registrationprocessing A in the setting mode and pre-processing B and evaluationprocessing C in the operation mode. An example is explained in which, insuch a series of image processing, the image-processing-conditionallocating unit 55 i changes a part of the image processing and changesthe pre-processing B to pre-processing D as shown in FIGS. 51A and 51B.

It is assumed that, in the two-point registration of the non-defectiveproduct image and the background image explained above, theimage-processing-condition allocating unit 51 i acquires a non-defectiveproduct-background differential image in the setting mode, registers thenon-defective product-background differential image as a model image,and calculates a matching degree of the model image and the input imageand performs the pass/fail determination in the operation mode.

Specifically, in the registration processing A shown in FIG. 51A, thedifference extracting unit extracts a difference from the non-defectiveproduct image GDI shown in FIG. 51C and the background image BGI shownin FIG. 51E and cuts out work as shown in FIG. 51G. Further, thedifference extracting unit extracts feature values of the work from anobtained image of the work. For example, the feature-value extractingunit 56 b calculates a luminance average value of 75, luminancedispersion of 30, the number of edge pixels of 50, and the like asfeature values from the image of the work shown in FIG. 51G. Afterperforming the registration processing A in advance in the setting modein this way, the image-processing-condition allocating unit 51 iperforms the pre-processing B and the evaluation processing C in theoperation mode. Note that processing that needs to be performed within adesignated response time, in other words, image processing that needs tobe reduced in time is not the processing in the setting mode and is thepre-processing B and the evaluation processing C in the operation mode.

In the pre-processing B, in an evaluation image (FIG. 51F) of anevaluation target obtained as an input image, theimage-processing-condition allocating unit 51 i searches for the work(FIG. 51G) cut out in the registration processing A. Consequently, thework is specified from the evaluation image as shown in FIG. 51H.

In the evaluation processing C, the image-processing-conditionallocating unit 51 i extracts and evaluates feature values with respectto a work region (FIG. 51J) cut out from the evaluation image (FIG.51H). Further, the image-processing-condition allocating unit 51 icompares the feature values with feature values already extracted in theregistration processing A and calculates a matching degree. For example,the feature-value extracting unit 56 b calculates, as feature values,the luminance average value of 70, the luminance dispersion of 30, thenumber of edge pixels of 55, and the like from the work region shown inFIG. 51J. The pass/fail determining unit 57 d compares the obtainedfeature values of the work region and the feature values of the image ofthe work explained above and performs the pass/fail determination.

In the image processing explained above, a processing time in thepre-processing B is long. Therefore, when a set response time is short,the pre-processing B and the evaluation processing C sometimes cannot beended within the response time in the operation mode. In this case, asshown in FIG. 51B, the image-processing-condition allocating unit 55 ichanges the pre-processing B to the pre-processing D having a lighterload. In the pre-processing D, for example, as shown in FIG. 51I, theimage-processing-condition allocating unit 51 i performs differentialprocessing with the background image BGI (FIG. 51E) instead ofperforming a search for a work image on the evaluation image (FIG. 51F).Consequently, it is possible to cut out, from the evaluation image shownin FIG. 51F, a region of the work as shown in FIG. 51I. Consequently,for a common purpose of removal of a background from the valuationimage, the image search is replaced with the pre-processing moresimplified than the image search. Consequently, a reduction inprocessing time is achieved. It is possible to end the image processingwithin the response time.

(Change of Constituent Elements of the Image Processing Algorithm)

In the example explained above, the method is explained in which theimage-processing-condition allocating unit 55 i replaces the imageprocessing algorithm in the image processing. However, a method in whichthe image-processing-condition allocating unit 55 i changes theconditions of the image processing is not limited to the replacement ofthe image processing algorithm and can be other methods. As anotherexample in which the image-processing-condition allocating unit 55 ichanges the conditions of the image processing, an example in which theimage-processing-condition allocating unit 55 i changes constituentelements of the image processing flow is explained with reference toflowcharts of FIGS. 52A and 52B. It is assumed that images treated inthis example (the non-defective product image GDI, the defective productimage NGI, the background image BGI, and an evaluation image) are thesame as the images shown in FIGS. 51C to 51F and a series of imageprocessing before the conditions of the image processing are changed isas shown in FIG. 52A and is the same as the image processing shown inFIG. 51A explained above.

First, in registration processing A′ in the setting mode after a change,the image-processing-condition allocating unit 51 i specifies workaccording to a difference between the non-defective product image GDI(FIG. 51C) and the background image BGI (FIG. 51E) and further extractsfeature values of work. The image processing is the same as theregistration processing A shown in FIG. 51A (FIG. 52A). However, in theextraction of the feature values, in the registration processing A′,image processing parameters of the image processing algorithm arechanged from the image processing parameters in the registrationprocessing A. Specifically, in the registration processing A, theimage-processing-condition allocating unit 51 i uses a Sobel filter forextraction of an “edge feature” among the feature values. On the otherhand, in the registration processing A′ shown in FIG. 52B, theimage-processing-condition allocating unit 51 i uses a 2×2 Robertsfilter for the extraction of the “edge feature”.

As the Sobel filter, as shown in FIGS. 53A and 53B, theimage-processing-condition allocating unit 51 i applies two filters ofSobel X (FIG. 53A) and Sobel Y (FIG. 53B) to eight pixels near a targetpixel. Thereafter, when an X component of an edge applied with the SobelX and a Y component of an edge applied with the Sobel Y are respectivelyrepresented as Sx and Sy (FIG. 53C), the image-processing-conditionallocating unit 51 i calculates intensity =√ (Sx²+Sy²) and anangle=Arctan(Sy/Sx). Note that a 3×3 Sobel filter is used. However, theSobel filter is not limited to this. For example, other Sobel filterssuch as a 5×5 Sobel filter may be used.

On the other hand, the Roberts filter is image processing obtained bysimplifying the Sobel filter. Specifically, theimage-processing-condition allocating unit 51 i applies, instead of theSobel X and the Sobel Y, filters of Roberts X and Roberts Y shown inFIGS. 54A and 54B obtained by simplifying the Sobel X and the Sobel Y.The image-processing-condition allocating unit 51 i calculates, as inthe Sobel filter, intensity =√ (Sx′²+Sy′²) and an angle=Arctan (Sy′/Sx′)from Sx′ and Sy′ (FIG. 54C), which are an X component of an edge appliedwith the Roberts X and a Y component of an edge applied with the RobertsY. As a result, as the feature values of the work, for example, theluminance average value of 75, the luminance dispersion of 30, thenumber of edge pixels of 50, and the like are calculated.

After performing the image processing in the setting mode first in thisway, the image-processing-condition allocating unit 51 i performs thepre-processing B and the evaluation processing C and C′, which are theimage processing in the setting mode. In the pre-processing B, in bothof FIGS. 52A and 52B, as in the pre-processing B shown in FIG. 51A, theimage-processing-condition allocating unit 51 i searches for cut-outwork in the evaluation image (FIG. 51F) and cuts out the work from theevaluation image (FIG. 51H).

Further, in the evaluation processing C and C′, theimage-processing-condition allocating unit 51 i extracts and evaluatesfeatures of the work region (FIG. 51J) cut out from the evaluationimage. In the evaluation processing C shown in FIG. 52A, a Sobel filtersame as the Sobel filter in the registration processing A is used. Onthe other hand, in the evaluation processing C′ shown in FIG. 52B afterthe change, a Roberts filter same as the Roberts filter in theregistration processing A is used. The image-processing-conditionallocating unit 51 i compares feature values of the evaluation imageobtained using the Roberts filter with the feature values alreadyextracted in the registration processing A and calculates a matchingdegree. In this way, it is possible to reduce the processing time bysimplifying the method of the edge extraction with respect to the commonimage processing of the edge extraction, which is one of the constituentelements of the image processing, and ends the image processing withinthe set response time.

In the example explained above, the example is explained in which theimage-processing-condition allocating unit performs one of the change ofthe image processing algorithm itself and the change of the constituentelements of the image processing algorithm. However, the presentinvention is not limited to this. For example, the change of the imageprocessing algorithm and the change of the constituent elements of theimage processing algorithm can be combined. Besides changing already setimage processing content according to a response time, theimage-processing-condition allocating unit can also use the imageprocessing content for initial operation for allocating appropriateimage processing in a state in which a response time is given inadvance.

Further, a change of the image processing parameters in the imageprocessing algorithm may be applied. For example, a size of the Sobelfilter may be changed from 3×3 to 5×5 and the like. In this way, theimage-processing-condition allocating unit 55 i can change a filter sizeof an edge filer for edge extraction of a non-defective product image inthe setting mode and edge extraction of an input image in the operationmode.

Note that, besides being configured by a single image processingalgorithm, the image processing may be configured by a plurality ofdifferent image processing algorithms. In both the cases, theimage-processing-condition allocating unit can change all or a part ofthe image processing algorithms and the image processing parameters suchthat a determination result by the pass/fail determining unit 57 d isoutput within the response time.

The matching-degree calculating unit 57 c may be configured tocalculate, in the operation mode, a matching degree of an input image toa model image for each of the plurality of different image processingalgorithms.

Further, in the example explained above, in the two-point registrationof the non-defective product image and the background image, thenon-defective product-background differential image is used as the modelimage. However, the present invention is not limited to this. Forexample, in the two-point registration of the non-defective productimage and the defective product image, a non-defective product-defectiveproduct differential image may be used as the model image.Alternatively, in the three-point registration of the non-defectiveproduct image GDI, the defective product image NGI (FIG. 51D), and thebackground image BGI, when the model image corresponding to thenon-defective product-background differential image and the model imagecorresponding to the defective product-background differential image areregistered in the setting mode and matching degrees of the model imageof the non-defective product-background differential image and the modelimage of the defective product-background differential image and theinput image are respectively calculated and the pass/fail determinationis performed in the operation mode, the image-processing-conditionallocating unit can also change the conditions of the image processing.Alternatively, in the one-point registration for registering thebackground image, when the background image is set as the model imageand a matching degree with the input image is calculated, theimage-processing-condition allocating unit can change the conditions ofthe image processing.

In the example explained above, the matching-degree calculating unit 57c calculates the matching degree indicating the degree of matching ofthe feature values of the model image and the input image. The modelimage serving as a base for calculating the matching degree isconfigured according to the non-defective product image, the defectiveproduct image, and the background image registered by the image/settingstoring unit 54. For example, the model image can be variousdifferential images, compressed differential images obtained bycompressing the differential images, or an edge image. Instead of themodel image, feature values may be calculated on the basis ofinformation other than images. For example, the matching-degreecalculating unit may calculate a matching degree on the basis of featurevalues such as an edge and luminance. In this way, a base of thecalculation of the matching degree by the matching-degree calculatingunit is not always limited to image data. Other information includingfeature values such as an edge and luminance can also be used. In thisspecification, the information forming the base of the matching degreecalculation is referred to as pattern model.

With the image processing sensor, the image processing method, the imageprocessing program, and the computer-readable recording medium and thedevice having the image processing program recorded therein, it ispossible to suitably perform a non-defective product inspection and adefective product inspection using images having a fixed spread insteadof a photoelectric sensor set in a manufacturing line.

What is claimed is:
 1. An image processing sensor for performingpredetermined image processing on an image of an inspection targetobject to detect that the inspection target object is a non-defectiveproduct or a defective product, the image processing sensor comprising:an imaging unit configured to image the inspection target object; apass/fail determining unit configured to perform, on the basis of aninput image of the inspection target object acquired by the imagingunit, pass/fail determination for distinguishing pass/fail of theinspection target object; an image registering unit configured to, in asetting mode for calculating a threshold serving as a reference of thepass/fail determination used in an operation mode for distinguishing thepass/fail of the inspection target object by the pass/fail determiningunit, acquire, with the imaging unit, an image including the inspectiontarget object that should be distinguished as the non-defective productby the pass/fail determining unit and register the image as anon-defective product image, acquire, with the imaging unit, an imageincluding the inspection target object that should be distinguished asthe defective product by the pass/fail determining unit and register theimage as a defective product image, and acquire, with the imaging unit,an image of a background from which a feature portion of thenon-defective product in the inspection target object is removed andregister the image as a background image; a differential-imagegenerating unit configured to generate a first differential image fromthe non-defective product image and the background image registered bythe image registering unit and generate a second differential image fromthe defective product image and the background image registered by theimage registering unit; a matching-degree calculating unit configured tocalculate a matching degree indicating a degree of feature matching ofthe second differential image with respect to a model imagecorresponding to the first differential image generated by thedifferential-image generating unit; and a threshold calculating unitconfigured to calculate, on the basis of the matching degree calculatedby the matching-degree calculating unit, a threshold used in theoperation mode.
 2. The image processing sensor according to claim 1,further comprising: a display unit configured to display an image of theinspection target object acquired by the imaging unit; an operation unitconfigured to receive an operation instruction for registering the imagedisplayed by the display unit; and a display control unit configured tocause the display unit to display the non-defective product image as alive image on a first registration screen for registering thenon-defective product image on the basis of the operation instructionreceived from the operation unit, cause the display unit to display thedefective product image as the live image on a second registrationscreen for registering the defective product image on the basis of theoperation instruction received from the operation unit, and cause thedisplay unit to display the background image as the live image on athird registration screen for registering the background image on thebasis of the operation instruction received from the operation unit,wherein the image registering unit registers, on the basis of a firstinstruction received from the operation unit, the non-defective productimage displayed by the display unit on the first registration screen,register, on the basis of a second instruction received from theoperation unit, the defective product image displayed by the displayunit on the second registration screen, and register, on the basis of athird instruction received from the operation unit, the background imagedisplayed by the display unit on the third registration screen.
 3. Theimage processing sensor according to claim 2, wherein the displaycontrol unit causes the display unit to display, on the secondregistration screen, as a still image, the non-defective product imageregistered on the first registration screen by the image registeringunit.
 4. The image processing sensor according to claim 1, furthercomprising an operation/setting-mode switching unit configured to switchthe operation mode for distinguishing the pass/fail of the inspectiontarget object with the pass/fail determining unit and the setting modefor calculating a threshold used in the operation mode.
 5. The imageprocessing sensor according to claim 4, further comprising ateaching-mode switching unit configured to selectively switch, in thesetting mode switched by the operation/setting-mode switching unit, asecond teaching mode for switching and displaying, on the display unit,any one of the first registration screen, the second registrationscreen, and the third registration screen and a first teaching mode forswitching and displaying, on the display unit, one of the firstregistration screen and the third registration screen, wherein when thesecond teaching mode is selected by the teaching-mode switching unit,the display control unit causes the display unit to display thenon-defective product image as a live image on the first registrationscreen, causes the display unit to display the defective product imageas the live image on the second registration screen, and causes thedisplay unit to display the background image as the live image on thethird registration screen, and on the other hand, when the firstteaching mode is selected by the teaching-mode switching unit, thedisplay control unit causes the display unit to display thenon-defective product image as the live image on the first registrationscreen and causes the display unit to display the background image asthe live image on the third registration screen.
 6. The image processingsensor according to claim 4, further comprising a teaching-modeswitching unit configured to selectively switch, in the setting modeswitched by the operation/setting-mode switching unit, a second teachingmode for switching and displaying, on the display unit, any one of thefirst registration screen, the second registration screen, and the thirdregistration screen and a first teaching mode for switching anddisplaying, on the display unit, one of the first registration screenand the third registration screen, wherein when the first teaching modeis selected by the teaching-mode switching unit, the differential-imagegenerating unit generates the first differential image from thenon-defective product image and the background image and thematching-degree calculating unit calculates a matching degree indicatinga degree of feature matching of the background image with respect to themodel image corresponding to the first differential image generated bythe differential-image generating unit.
 7. The image processing sensoraccording to claim 6, further comprising a feature-region extractingunit configured to extract feature image regions from the firstdifferential image and the second differential image, wherein thematching-degree calculating unit calculates a matching degree indicatinga degree of feature matching of the second differential image withrespect to the feature image region extracted from the firstdifferential image by the feature-region extracting unit.
 8. The imageprocessing sensor according to claim 6, wherein the model image includesa differential image or an edge image.
 9. The image processing sensoraccording to claim 5, wherein the teaching-mode switching unit isfurther capable of selecting a third teaching mode for displaying thethird registration screen on the display unit in the setting modeswitched by the operation/setting-mode switching unit, and when thethird teaching mode is selected by the teaching-mode switching unit, thematching-degree calculating unit calculates a feature value of thebackground image registered by the image registering unit, and thethreshold calculating unit calculates, on the basis of the feature valueof the background image calculated by the matching-degree calculatingunit, a threshold used in the operation mode.
 10. The image processingsensor according to claim 1, wherein the display control unit at leastcauses the display unit to display, on the first registration screen,first induction information for inducing registration of thenon-defective product image and causes the display unit to display, onthe third registration screen, third induction information for inducingregistration of the background image.
 11. The image processing sensoraccording to claim 10, wherein the display control unit at least causesthe display unit to display, on the second registration screen, secondinduction information for inducing registration of the defective productimage.
 12. The image processing sensor according to claim 1, wherein thedisplay control unit provides, in the display unit, an image displayregion where an image is displayed and causes the display unit todisplay, in the image display region, guide lines serving as indicatorsfor positioning in placing the inspection target object in an imagingposition.
 13. The image processing sensor according to claim 1, whereinthe display control unit is capable of displaying, on the display unit,registration order information indicating registration order forperforming image registration of the non-defective product image, thedefective product image, or the background image.
 14. An imageprocessing method for performing predetermined image processing on animage of an inspection target object to detect that the inspectiontarget object is a non-defective product or a defective product, theimage processing method comprising: a step of, in a setting mode forcalculating a threshold serving as a reference of pass/faildetermination used in an operation mode for distinguishing pass/failwith a pass/fail determining unit configured to determine pass/fail ofthe inspection target object, acquiring, with an imaging unit configuredto image the inspection target object, an image including the inspectiontarget object that should be distinguished as the non-defective productby the pass/fail determining unit and registering the image as anon-defective product image with an image registering unit, acquiring,with the imaging unit, an image including the inspection target objectthat should be distinguished as the defective product by the pass/faildetermining unit and registering the image as a defective product imagewith the image registering unit, and acquiring, with the imaging unit,an image of a background from which a feature portion of thenon-defective product in the inspection target object is removed andregistering the image as a background image with the image registeringunit; a step of generating a first differential image from thenon-defective product image and the background image registered by theimage registering unit and generating a second differential image fromthe defective product image and the background image registered by theimage registering unit; a step of calculating a matching degreeindicating a degree of feature matching of the second differential imagewith respect to a model image corresponding to the first differentialimage; and a step of calculating, on the basis of the matching degree, athreshold used in the operation mode.
 15. An image processing programfor performing predetermined image processing on an image of aninspection target object to detect that the inspection target object isa non-defective product or a defective product, the image processingprogram causing a computer to realize: in a setting mode for calculatinga threshold serving as a reference of pass/fail determination used in anoperation mode for distinguishing pass/fail with a pass/fail determiningunit configured to determine pass/fail of the inspection target object,a function of acquiring, with an imaging unit, an image including theinspection target object that should be distinguished as thenon-defective product by the pass/fail determining unit and registeringthe image as a non-defective product image; a function of acquiring,with the imaging unit, an image including the inspection target objectthat should be distinguished as the defective product by the pass/faildetermining unit and registering the image as a defective product image;and a function of acquiring, with the imaging unit, an image of abackground from which a feature portion of the non-defective product inthe inspection target object is removed and registering the image as abackground image; a function of generating a first differential imagefrom the registered non-defective product image and the registeredbackground image and generating a second differential image from thedefective product image and the background image; a function ofcalculating a matching degree indicating a degree of feature matching ofthe second differential image with respect to a model imagecorresponding to the first differential image; and a function ofcalculating, on the basis of the matching degree, a threshold used inthe operation mode.
 16. A computer-readable recording medium having thecomputer program according to claim 15 recorded therein or a devicehaving the computer program according to claim 15 stored therein.